Using twenty long-term 3D core-collapse supernova simulations, we find that lower compactness progenitors that explode quasi-spherically due to the short delay to explosion experience smaller neutron
star recoil kicks in the ∼100−200 km s−1
range, while higher compactness progenitors that explode
later and more aspherically leave neutron stars with kicks in the ∼300−1000 km s−1
range. In addition, we find that these two classes are correlated with the gravitational mass of the neutron star.
This correlation suggests that the survival of binary neutron star systems may in part be due to their
lower kick speeds. We also find a correlation of the kick with both the mass dipole of the ejecta
and the explosion energy. Furthermore, one channel of black hole birth leaves masses of ∼10 M⊙, is
not accompanied by a neutrino-driven explosion, and experiences small kicks. A second is through
a vigorous explosion that leaves behind a black hole with a mass of ∼3.0 M⊙ kicked to high speeds.
We find that the induced spins of nascent neutron stars range from seconds to ∼10 milliseconds and
that a spin/kick correlation for pulsars emerges naturally. We suggest that if an initial spin biases
the explosion direction, a spin/kick correlation is a common byproduct of the neutrino mechanism of
core-collapse supernovae. Finally, the induced spin in explosive black hole formation is likely large and
in the collapsar range. This new 3D model suite provides a greatly expanded perspective and appears
to explain some observed pulsar properties by default.
Asymmetrical tidal tails of open star clusters: stars crossing their cluster’...Sérgio Sacani
The document discusses asymmetrical tidal tails observed around five open star clusters, which challenges Newtonian gravity. It summarizes how tidal tails form as stars escape clusters due to energy equipartition. Observations of the Hyades, Praesepe, Coma Berenices, COIN-Gaia 13, and NGC 752 clusters found more stars in the leading tidal tails within 50 pc of the clusters. Simulations show that in Newtonian gravity, tidal tails should be symmetrical, but asymmetries can arise in Milgromian dynamics. Future work is needed to better map tidal tails and develop Milgromian simulations.
Detection of anisotropic satellite quenching in galaxy clusters up to z ∼ 1Sérgio Sacani
Satellite galaxies in the cluster environment are more likely to be quenched than galaxies in the general field. Recently, it has
been reported that satellite galaxy quenching depends on the orientation relative to their central galaxies: satellites along the
major axis of centrals are more likely to be quenched than those along the minor axis. In this paper, we report a detection
of such anisotropic quenching up to z ∼ 1 based on a large optically selected cluster catalogue constructed from the Hyper
Suprime-Cam Subaru Strategic Program. We calculate the quiescent satellite galaxy fraction as a function of orientation angle
measured from the major axis of central galaxies and find that the quiescent fractions at 0.25 < z < 1 are reasonably fitted
by sinusoidal functions with amplitudes of a few per cent. Anisotropy is clearer in inner regions (<r200m) of clusters and not
significant in cluster outskirts (>r200m). We also confirm that the observed anisotropy cannot be explained by differences in
local galaxy density or stellar mass distribution along the two axes. Quiescent fraction excesses between the two axes suggest
that the quenching efficiency contributing to the anisotropy is almost independent of stellar mass, at least down to our stellar
mass limit of M∗ = 1 × 1010 M. Finally, we argue that the physical origins of the observed anisotropy should have shorter
quenching time-scales than ∼ 1 Gyr, like ram-pressure stripping, because, for anisotropic quenching to be observed, satellites
must be quenched before their initial orientation angles are significantly changed.
GRMHD Simulations of Neutron-star Mergers with Weak Interactions: r-process N...Sérgio Sacani
Fast neutron-rich material ejected dynamically over 10 ms during the merger of a binary neutron star (BNS) can
give rise to distinctive electromagnetic counterparts to the system’s gravitational-wave emission that serve as a
“smoking gun” to distinguish between a BNS and an NS–black hole merger. We present novel ab initio modeling
of the kilonova precursor and kilonova afterglow based on 3D general-relativistic magnetohydrodynamic
simulations of BNS mergers with nuclear, tabulated, finite-temperature equations of state (EOSs), weak
interactions, and approximate neutrino transport. We analyze dynamical mass ejection from 1.35–1.35 Me
binaries, consistent with properties of the first observed BNS merger GW170817, using three nuclear EOSs that
span the range of allowed compactness of 1.35 Me-neutron stars. Nuclear reaction network calculations yield a
robust second-to-third-peak r-process. We find few ×10−6 Me of fast (v > 0.6c) ejecta that give rise to broadband
synchrotron emission on ∼years timescales, consistent with tentative evidence for excess X-ray/radio emission
following GW170817. We find ≈2 × 10−5 Me of free neutrons that power a kilonova precursor on hours
timescale. A boost in early UV/optical brightness by a factor of a few due to previously neglected relativistic
effects, with enhancements up to 10 hr post-merger, is promising for future detection with UV/optical telescopes
like Swift or ULTRASAT. We find that a recently predicted opacity boost due to highly ionized lanthanides at
70,000 K is unlikely to affect the early kilonova based on the obtained ejecta structures. Azimuthal
inhomogeneities in dynamical ejecta composition for soft EOSs found here (“lanthanide/actinide pockets”) may
have observable consequences for both early kilonova and late-time nebular emission.
JWST early Universe observations and 𝚲CDM cosmologySérgio Sacani
Deep space observations of the James Webb Space Telescope (JWST) have revealed that the structure and
masses of very early Universe galaxies at high redshifts (𝑧~15), existing at ~0.3 Gyr after the BigBang,
may be as evolved as the galaxies in existence for ~10 Gyr. The JWST findings are thus in strong tension
with the ΛCDM cosmological model. While tired light (TL) models have been shown to comply with the
JWST angular galaxy size data, they cannot satisfactorily explain isotropy of the cosmic microwave
background (CMB) observations or fit the supernovae distance modulus vs. redshift data well. We have
developed hybrid models that include the tired light concept in the expanding universe. The hybrid ΛCDM
model fits the supernovae type 1a data well but not the JWST observations. We present a model with
covarying coupling constants (CCC), starting from the modified FLRW metric and resulting Einstein and
Friedmann equations, and a CCC+TL hybrid model. They fit the Pantheon+ data admirably, and the
CCC+TL model is compliant with the JWST observations. It stretches the age of the universe to 26.7 Gyr
with 5.8 Gyr at 𝑧 = 10 and 3.5 Gyr at 𝑧 = 20, giving enough time to form massive galaxies. It thus
resolves the 'impossible early galaxy' problem without requiring the existence of primordial black hole
seeds or modified power spectrum, rapid formation of massive population III stars, and super Eddington
accretion rates. One could infer the CCC model as an extension of the ΛCDM model with a dynamic
cosmological constant.
3D-Spatiotemporal forecasting the expansion of supernova shells using deep le...Sérgio Sacani
Supernova (SN) plays an important role in galaxy formation and evolution. In high-resolution galaxy simulations using massively
parallel computing, short integration time-steps for SNe are serious bottlenecks. This is an urgent issue that needs to be resolved
for future higher-resolution galaxy simulations. One possible solution would be to use the Hamiltonian splitting method, in
which regions requiring short time-steps are integrated separately from the entire system. To apply this method to the particles
affected by SNe in a smoothed particle hydrodynamics simulation, we need to detect the shape of the shell on and within which
such SN-affected particles reside during the subsequent global step in advance. In this paper, we develop a deep learning model,
3D-Memory In Memory (3D-MIM), to predict a shell expansion after a SN explosion. Trained on turbulent cloud simulations
with particle mass mgas = 1 M, the model accurately reproduces the anisotropic shell shape, where densities decrease by over
10 per cent by the explosion. We also demonstrate that the model properly predicts the shell radius in the uniform medium
beyond the training data set of inhomogeneous turbulent clouds. We conclude that our model enables the forecast of the shell
and its interior where SN-affected particles will be present.
The SPHERE view of three interacting twin disc systems in polarised lightSérgio Sacani
Dense stellar environments as hosts of ongoing star formation increase the probability of gravitational encounters among stellar
systems during the early stages of evolution. Stellar interaction may occur through non-recurring, hyperbolic or parabolic passages
(a so-called ‘fly-by’), through secular binary evolution, or through binary capture. In all three scenarios, the strong gravitational
perturbation is expected to manifest itself in the disc structures around the individual stars. Here, we present near-infrared
polarised light observations that were taken with the SPHERE/IRDIS instrument of three known interacting twin-disc systems:
AS 205, EM* SR 24, and FU Orionis. The scattered light exposes spirals likely caused by the gravitational interaction. On
a larger scale, we observe connecting filaments between the stars. We analyse their very complex polarised intensity and put
particular attention to the presence of multiple light sources in these systems. The local angle of linear polarisation indicates
the source whose light dominates the scattering process from the bridging region between the two stars. Further, we show
that the polarised intensity from scattering with multiple relevant light sources results from an incoherent summation of the
individuals’ contribution. This can produce nulls of polarised intensity in an image, as potentially observed in AS 205.We discuss
the geometry and content of the systems by comparing the polarised light observations with other data at similar resolution,
namely with ALMA continuum and gas emission. Collective observational data can constrain the systems’ geometry and stellar
trajectories, with the important potential to differentiate between dynamical scenarios of stellar interaction.
The xmm newton-view_of_the_central_degrees_of_the_milk_waySérgio Sacani
Novas imagens do Observatório de Raios-X XMM-Newton da ESA revelaram alguns dos processos mais intensos que acontecem no coração da nossa Via Láctea.
As fontes brilhantes e pontuais que se destacam por toda imagem indicam os sistemas estelares binários onde uma das estrelas atingiu o final de sua vida, desenvolvendo para um objeto compacto e denso – uma estrela de nêutrons ou um buraco negro.
A região central da Via Láctea também contém jovens estrelas e aglomerados estelares e algumas dessas fontes são visíveis como pontos brancos e vermelhos brilhando na imagem, que se espalha por 1000 anos-luz.
A maior parte da ação ocorre no centro, onde nuvens difusas de gás estão sendo cavadas por ventos poderosos soprados por estrelas jovens, bem como por supernovas.
Prospects for Detecting Gaps in Globular Cluster Stellar Streams in External ...Sérgio Sacani
Stellar streams form through the tidal disruption of satellite galaxies or globular clusters orbiting a
host galaxy. Globular cluster streams are exciting since they are thin (dynamically cold) and, therefore
sensitive to perturbations from low-mass subhalos. Since the subhalo mass function differs depending
on the dark matter composition, these gaps can provide unique constraints on dark matter models.
However, current samples are limited to the Milky Way. With its large field of view, deep imaging
sensitivity, and high angular resolution, the upcoming Nancy Grace Roman Space Telescope (Roman)
presents a unique opportunity to increase the number of observed streams and gaps significantly. This
paper presents a first exploration of the prospects for detecting gaps in streams in M31 and other
nearby galaxies with resolved stars. We simulate the formation of gaps in a Palomar-5-like stream
and generate mock observations of these gaps with background stars in M31 and the foreground Milky
Way stellar fields. We assess Roman’s ability to detect gaps out to 10 Mpc through visual inspection
and with the gap-finding tool FindTheGap. We conclude that gaps of ≈ 1.5 kpc in streams that are
created from subhalos of masses ≥ 5×106 M⊙ are detectable within a 2–3 Mpc volume in exposures of
1000s–1 hour. This volume contains ≈ 150 galaxies, including ≈ 8 galaxies with luminosities > 109 L⊙.
Large samples of stream gaps in external galaxies will open up a new era of statistical analyses of gap
characteristics in stellar streams and help constrain dark matter models.
Asymmetrical tidal tails of open star clusters: stars crossing their cluster’...Sérgio Sacani
The document discusses asymmetrical tidal tails observed around five open star clusters, which challenges Newtonian gravity. It summarizes how tidal tails form as stars escape clusters due to energy equipartition. Observations of the Hyades, Praesepe, Coma Berenices, COIN-Gaia 13, and NGC 752 clusters found more stars in the leading tidal tails within 50 pc of the clusters. Simulations show that in Newtonian gravity, tidal tails should be symmetrical, but asymmetries can arise in Milgromian dynamics. Future work is needed to better map tidal tails and develop Milgromian simulations.
Detection of anisotropic satellite quenching in galaxy clusters up to z ∼ 1Sérgio Sacani
Satellite galaxies in the cluster environment are more likely to be quenched than galaxies in the general field. Recently, it has
been reported that satellite galaxy quenching depends on the orientation relative to their central galaxies: satellites along the
major axis of centrals are more likely to be quenched than those along the minor axis. In this paper, we report a detection
of such anisotropic quenching up to z ∼ 1 based on a large optically selected cluster catalogue constructed from the Hyper
Suprime-Cam Subaru Strategic Program. We calculate the quiescent satellite galaxy fraction as a function of orientation angle
measured from the major axis of central galaxies and find that the quiescent fractions at 0.25 < z < 1 are reasonably fitted
by sinusoidal functions with amplitudes of a few per cent. Anisotropy is clearer in inner regions (<r200m) of clusters and not
significant in cluster outskirts (>r200m). We also confirm that the observed anisotropy cannot be explained by differences in
local galaxy density or stellar mass distribution along the two axes. Quiescent fraction excesses between the two axes suggest
that the quenching efficiency contributing to the anisotropy is almost independent of stellar mass, at least down to our stellar
mass limit of M∗ = 1 × 1010 M. Finally, we argue that the physical origins of the observed anisotropy should have shorter
quenching time-scales than ∼ 1 Gyr, like ram-pressure stripping, because, for anisotropic quenching to be observed, satellites
must be quenched before their initial orientation angles are significantly changed.
GRMHD Simulations of Neutron-star Mergers with Weak Interactions: r-process N...Sérgio Sacani
Fast neutron-rich material ejected dynamically over 10 ms during the merger of a binary neutron star (BNS) can
give rise to distinctive electromagnetic counterparts to the system’s gravitational-wave emission that serve as a
“smoking gun” to distinguish between a BNS and an NS–black hole merger. We present novel ab initio modeling
of the kilonova precursor and kilonova afterglow based on 3D general-relativistic magnetohydrodynamic
simulations of BNS mergers with nuclear, tabulated, finite-temperature equations of state (EOSs), weak
interactions, and approximate neutrino transport. We analyze dynamical mass ejection from 1.35–1.35 Me
binaries, consistent with properties of the first observed BNS merger GW170817, using three nuclear EOSs that
span the range of allowed compactness of 1.35 Me-neutron stars. Nuclear reaction network calculations yield a
robust second-to-third-peak r-process. We find few ×10−6 Me of fast (v > 0.6c) ejecta that give rise to broadband
synchrotron emission on ∼years timescales, consistent with tentative evidence for excess X-ray/radio emission
following GW170817. We find ≈2 × 10−5 Me of free neutrons that power a kilonova precursor on hours
timescale. A boost in early UV/optical brightness by a factor of a few due to previously neglected relativistic
effects, with enhancements up to 10 hr post-merger, is promising for future detection with UV/optical telescopes
like Swift or ULTRASAT. We find that a recently predicted opacity boost due to highly ionized lanthanides at
70,000 K is unlikely to affect the early kilonova based on the obtained ejecta structures. Azimuthal
inhomogeneities in dynamical ejecta composition for soft EOSs found here (“lanthanide/actinide pockets”) may
have observable consequences for both early kilonova and late-time nebular emission.
JWST early Universe observations and 𝚲CDM cosmologySérgio Sacani
Deep space observations of the James Webb Space Telescope (JWST) have revealed that the structure and
masses of very early Universe galaxies at high redshifts (𝑧~15), existing at ~0.3 Gyr after the BigBang,
may be as evolved as the galaxies in existence for ~10 Gyr. The JWST findings are thus in strong tension
with the ΛCDM cosmological model. While tired light (TL) models have been shown to comply with the
JWST angular galaxy size data, they cannot satisfactorily explain isotropy of the cosmic microwave
background (CMB) observations or fit the supernovae distance modulus vs. redshift data well. We have
developed hybrid models that include the tired light concept in the expanding universe. The hybrid ΛCDM
model fits the supernovae type 1a data well but not the JWST observations. We present a model with
covarying coupling constants (CCC), starting from the modified FLRW metric and resulting Einstein and
Friedmann equations, and a CCC+TL hybrid model. They fit the Pantheon+ data admirably, and the
CCC+TL model is compliant with the JWST observations. It stretches the age of the universe to 26.7 Gyr
with 5.8 Gyr at 𝑧 = 10 and 3.5 Gyr at 𝑧 = 20, giving enough time to form massive galaxies. It thus
resolves the 'impossible early galaxy' problem without requiring the existence of primordial black hole
seeds or modified power spectrum, rapid formation of massive population III stars, and super Eddington
accretion rates. One could infer the CCC model as an extension of the ΛCDM model with a dynamic
cosmological constant.
3D-Spatiotemporal forecasting the expansion of supernova shells using deep le...Sérgio Sacani
Supernova (SN) plays an important role in galaxy formation and evolution. In high-resolution galaxy simulations using massively
parallel computing, short integration time-steps for SNe are serious bottlenecks. This is an urgent issue that needs to be resolved
for future higher-resolution galaxy simulations. One possible solution would be to use the Hamiltonian splitting method, in
which regions requiring short time-steps are integrated separately from the entire system. To apply this method to the particles
affected by SNe in a smoothed particle hydrodynamics simulation, we need to detect the shape of the shell on and within which
such SN-affected particles reside during the subsequent global step in advance. In this paper, we develop a deep learning model,
3D-Memory In Memory (3D-MIM), to predict a shell expansion after a SN explosion. Trained on turbulent cloud simulations
with particle mass mgas = 1 M, the model accurately reproduces the anisotropic shell shape, where densities decrease by over
10 per cent by the explosion. We also demonstrate that the model properly predicts the shell radius in the uniform medium
beyond the training data set of inhomogeneous turbulent clouds. We conclude that our model enables the forecast of the shell
and its interior where SN-affected particles will be present.
The SPHERE view of three interacting twin disc systems in polarised lightSérgio Sacani
Dense stellar environments as hosts of ongoing star formation increase the probability of gravitational encounters among stellar
systems during the early stages of evolution. Stellar interaction may occur through non-recurring, hyperbolic or parabolic passages
(a so-called ‘fly-by’), through secular binary evolution, or through binary capture. In all three scenarios, the strong gravitational
perturbation is expected to manifest itself in the disc structures around the individual stars. Here, we present near-infrared
polarised light observations that were taken with the SPHERE/IRDIS instrument of three known interacting twin-disc systems:
AS 205, EM* SR 24, and FU Orionis. The scattered light exposes spirals likely caused by the gravitational interaction. On
a larger scale, we observe connecting filaments between the stars. We analyse their very complex polarised intensity and put
particular attention to the presence of multiple light sources in these systems. The local angle of linear polarisation indicates
the source whose light dominates the scattering process from the bridging region between the two stars. Further, we show
that the polarised intensity from scattering with multiple relevant light sources results from an incoherent summation of the
individuals’ contribution. This can produce nulls of polarised intensity in an image, as potentially observed in AS 205.We discuss
the geometry and content of the systems by comparing the polarised light observations with other data at similar resolution,
namely with ALMA continuum and gas emission. Collective observational data can constrain the systems’ geometry and stellar
trajectories, with the important potential to differentiate between dynamical scenarios of stellar interaction.
The xmm newton-view_of_the_central_degrees_of_the_milk_waySérgio Sacani
Novas imagens do Observatório de Raios-X XMM-Newton da ESA revelaram alguns dos processos mais intensos que acontecem no coração da nossa Via Láctea.
As fontes brilhantes e pontuais que se destacam por toda imagem indicam os sistemas estelares binários onde uma das estrelas atingiu o final de sua vida, desenvolvendo para um objeto compacto e denso – uma estrela de nêutrons ou um buraco negro.
A região central da Via Láctea também contém jovens estrelas e aglomerados estelares e algumas dessas fontes são visíveis como pontos brancos e vermelhos brilhando na imagem, que se espalha por 1000 anos-luz.
A maior parte da ação ocorre no centro, onde nuvens difusas de gás estão sendo cavadas por ventos poderosos soprados por estrelas jovens, bem como por supernovas.
Prospects for Detecting Gaps in Globular Cluster Stellar Streams in External ...Sérgio Sacani
Stellar streams form through the tidal disruption of satellite galaxies or globular clusters orbiting a
host galaxy. Globular cluster streams are exciting since they are thin (dynamically cold) and, therefore
sensitive to perturbations from low-mass subhalos. Since the subhalo mass function differs depending
on the dark matter composition, these gaps can provide unique constraints on dark matter models.
However, current samples are limited to the Milky Way. With its large field of view, deep imaging
sensitivity, and high angular resolution, the upcoming Nancy Grace Roman Space Telescope (Roman)
presents a unique opportunity to increase the number of observed streams and gaps significantly. This
paper presents a first exploration of the prospects for detecting gaps in streams in M31 and other
nearby galaxies with resolved stars. We simulate the formation of gaps in a Palomar-5-like stream
and generate mock observations of these gaps with background stars in M31 and the foreground Milky
Way stellar fields. We assess Roman’s ability to detect gaps out to 10 Mpc through visual inspection
and with the gap-finding tool FindTheGap. We conclude that gaps of ≈ 1.5 kpc in streams that are
created from subhalos of masses ≥ 5×106 M⊙ are detectable within a 2–3 Mpc volume in exposures of
1000s–1 hour. This volume contains ≈ 150 galaxies, including ≈ 8 galaxies with luminosities > 109 L⊙.
Large samples of stream gaps in external galaxies will open up a new era of statistical analyses of gap
characteristics in stellar streams and help constrain dark matter models.
Jet reorientation in central galaxies of clusters and groups: insights from V...Sérgio Sacani
Recent observations of galaxy clusters and groups with misalignments between their central AGN jets
and X-ray cavities, or with multiple misaligned cavities, have raised concerns about the jet – bubble
connection in cooling cores, and the processes responsible for jet realignment. To investigate the
frequency and causes of such misalignments, we construct a sample of 16 cool core galaxy clusters and
groups. Using VLBA radio data we measure the parsec-scale position angle of the jets, and compare
it with the position angle of the X-ray cavities detected in Chandra data. Using the overall sample
and selected subsets, we consistently find that there is a 30% – 38% chance to find a misalignment
larger than ∆Ψ = 45◦ when observing a cluster/group with a detected jet and at least one cavity. We
determine that projection may account for an apparently large ∆Ψ only in a fraction of objects (∼35%),
and given that gas dynamical disturbances (as sloshing) are found in both aligned and misaligned
systems, we exclude environmental perturbation as the main driver of cavity – jet misalignment.
Moreover, we find that large misalignments (up to ∼ 90◦
) are favored over smaller ones (45◦ ≤ ∆Ψ ≤
70◦
), and that the change in jet direction can occur on timescales between one and a few tens of Myr.
We conclude that misalignments are more likely related to actual reorientation of the jet axis, and we
discuss several engine-based mechanisms that may cause these dramatic changes.
Exploring Proxies for the Supermassive Black Hole Mass Function: Implications...Sérgio Sacani
Supermassive black holes (SMBHs) reside at the center of every massive galaxy in the local universe with masses
that closely correlate with observations of their host galaxy, implying a connected evolutionary history. The
population of binary SMBHs, which form following galaxy mergers, is expected to produce a gravitational-wave
background (GWB) detectable by pulsar timing arrays (PTAs). PTAs are starting to see hints of what may be a
GWB, and the amplitude of the emerging signal is toward the higher end of model predictions. Simulated
populations of binary SMBHs can be constructed from observations of galaxies and are used to make predictions
about the nature of the GWB. The greatest source of uncertainty in these observation-based models comes from the
inference of the SMBH mass function, which is derived from observed host galaxy properties. In this paper, I
undertake a new approach for inferring the SMBH mass function, starting from a velocity dispersion function
rather than a galaxy stellar mass function. I argue that this method allows for a more direct inference by relying on
a larger suite of individual galaxy observations as well as relying on a more “fundamental” SMBH mass relation. I
find that the resulting binary SMBH population contains more massive systems at higher redshifts than previous
models. Additionally, I explore the implications for the detection of individually resolvable sources in PTA data.
The hazardous km-sized NEOs of the next thousands of yearsSérgio Sacani
This document discusses methods for assessing the long-term impact risk of km-sized near-Earth objects (NEOs) over thousands of years. It analyzes the evolution of the Minimum Orbit Intersection Distance (MOID) between NEOs and Earth to identify objects that remain in close proximity for extended periods. It then estimates the probability of a deep Earth encounter during these low-MOID periods based on the growth of orbital uncertainties over time. This allows the authors to rank km-sized NEOs by their long-term impact hazard and identify targets that warrant further observation and analysis.
A vlt flames_survey_for_massive_binaries_in_westerlund_1Sérgio Sacani
1) The authors conducted a radial velocity survey of stars in the young massive cluster Westerlund 1 to search for a potential pre-supernova companion to the magnetar CXO J1647-10.2-455216 located within the cluster.
2) They identified a candidate star, Wd1-5, that has anomalous velocities compared to other stars in the cluster, suggesting it was impacted by the supernova that created the magnetar.
3) Analysis of Wd1-5 found evidence of chemical enrichment that is difficult to explain by single star evolution, but could be explained if Wd1-5 was once part of a close binary system where it accreted material from
A Neutron Star with a Massive Progenitor in Westerlund 1GOASA
1) The authors conducted a radial velocity survey of stars in the young massive cluster Westerlund 1 to search for a potential pre-supernova companion to the magnetar CXO J1647-10.2-455216 located within the cluster.
2) They identified a candidate star, Wd1-5, that has anomalous velocities compared to other stars in the cluster, suggesting it was impacted by the supernova of the magnetar's progenitor star.
3) Analysis of Wd1-5 found evidence of chemical enrichment that is difficult to explain by single star evolution, suggesting it was part of a binary system where it accreted material from the magnetar's progenitor prior to its
AT2023fhn (the Finch): a Luminous Fast Blue Optical Transient at a large offs...Sérgio Sacani
Luminous Fast Blue Optical Transients (LFBOTs) - the prototypical example being AT 2018cow - are a rare class of events
whose origins are poorly understood. They are characterised by rapid evolution, featureless blue spectra at early times, and
luminous X-ray and radio emission. LFBOTs thus far have been found exclusively at small projected offsets from star-forming
host galaxies. We present Hubble Space Telescope, Gemini, Chandra and Very Large Array observations of a new LFBOT,
AT 2023fhn. The Hubble Space Telescope data reveal a large offset (> 3.5 half-light radii) from the two closest galaxies, both
at redshift 𝑧 ∼ 0.24. The location of AT 2023fhn is in stark contrast with previous events, and demonstrates that LFBOTs can
occur in a range of galactic environments.
Formation of low mass protostars and their circumstellar disksSérgio Sacani
Understanding circumstellar disks is of prime importance in astrophysics, however, their birth process remains poorly constrained due to observational and numerical challenges. Recent numerical works have shown that the small-scale physics, often wrapped into a sub-grid model, play a crucial role in disk formation and evolution. This calls for a combined approach in which both the protostar and circumstellar disk are studied in concert. Aims. We aim to elucidate the small scale physics and constrain sub-grid parameters commonly chosen in the literature by resolving the star-disk interaction. Methods. We carry out a set of very high resolution 3D radiative-hydrodynamics simulations that self-consistently describe the collapse of a turbulent dense molecular cloud core to stellar densities. We study the birth of the protostar, the circumstellar disk, and its early evolution (< 6 yr after protostellar formation). Results. Following the second gravitational collapse, the nascent protostar quickly reaches breakup velocity and sheds its surface material, thus forming a hot (∼ 103 K), dense, and highly flared circumstellar disk. The protostar is embedded within the disk, such that material can flow without crossing any shock fronts. The circumstellar disk mass quickly exceeds that of the protostar, and its kinematics are dominated by self-gravity. Accretion onto the disk is highly anisotropic, and accretion onto the protostar mainly occurs through material that slides on the disk surface. The polar mass flux is negligible in comparison. The radiative behavior also displays a strong anisotropy, as the polar accretion shock is shown to be supercritical whereas its equatorial counterpart is subcritical. We also f ind a remarkable convergence of our results with respect to initial conditions. Conclusions. These results reveal the structure and kinematics in the smallest spatial scales relevant to protostellar and circumstellar disk evolution. They can be used to describe accretion onto regions commonly described by sub-grid models in simulations studying larger scale physics.
The Sparkler: Evolved High-redshift Globular Cluster Candidates Captured by JWSTSérgio Sacani
This document discusses compact red sources detected around a strongly lensed galaxy ("the Sparkler") at a redshift of 1.378 using JWST data. Photometry and morphological fits of the sources suggest they are spatially unresolved, very red, and consistent with old stellar populations. Spectroscopy shows emission from the galaxy but no signs of star formation in the red sources. The sources are most likely evolved globular clusters dating back to formation redshifts between 7-11, corresponding to ages of 3.9-4.1 billion years at the time of observation. If confirmed, these would be the first observed globular clusters at high redshift, opening a window into early globular cluster formation in the first billion years of
Is Betelgeuse Really Rotating? Synthetic ALMA Observations of Large-scale Con...Sérgio Sacani
The evolved stages of massive stars are poorly understood, but invaluable constraints can be derived from spatially resolved observations of nearby red supergiants, such as Betelgeuse. Atacama Large Millimeter/submillimeter Array (ALMA) observations of Betelgeuse showing a dipolar velocity field have been interpreted as evidence for a projected rotation rate of about 5 km s−1. This is 2 orders of magnitude larger than predicted by single-star evolution, which led to suggestions that Betelgeuse is a binary merger. We propose instead that large-scale convective motions can mimic rotation, especially if they are only partially resolved. We support this claim with 3D CO5BOLDsimulations of nonrotating red supergiants that we postprocessed to predict ALMA images and SiO spectra. We show that our synthetic radial velocity maps have a 90% chance of being falsely interpreted as evidence for a projected rotation rate of 2 km s−1 or larger for our fiducial simulation. We conclude that we need at least another ALMA observation to firmly establish whether Betelgeuse is indeed rapidly rotating. Such observations would also provide insight into the role of angular momentum and binary interaction in the late evolutionary stages. The data will further probe the structure and complex physical processes in the atmospheres of red supergiants, which are immediate progenitors of supernovae and are believed to be essential in the formation of gravitational-wave sources.
Exploring the nature and synchronicity of early cluster formation in the Larg...Sérgio Sacani
We analyse Hubble Space Telescope observations of six globular clusters in the Large Magel- lanic Cloud (LMC) from programme GO-14164 in Cycle 23. These are the deepest available observations of the LMC globular cluster population; their uniformity facilitates a precise comparison with globular clusters in the Milky Way. Measuring the magnitude of the main- sequence turn-off point relative to template Galactic globular clusters allows the relative ages of the clusters to be determined with a mean precision of 8.4 per cent, and down to 6 per cent for individual objects. We find that the mean age of our LMC cluster ensemble is identical to the mean age of the oldest metal-poor clusters in the Milky Way halo to 0.2 ± 0.4 Gyr. This provides the most sensitive test to date of the synchronicity of the earliest epoch of globular cluster formation in two independent galaxies. Horizontal branch magnitudes and subdwarf fitting to the main sequence allow us to determine distance estimates for each cluster and examine their geometric distribution in the LMC. Using two different methods, we find an average distance to the LMC of 18.52 ± 0.05.
PROBING THE SOLAR INTERIOR WITH LENSED GRAVITATIONAL WAVES FROM KNOWN PULSARSSérgio Sacani
When gravitational waves (GWs) from a spinning neutron star arrive from behind the Sun, they are
subjected to gravitational lensing that imprints a frequency-dependent modulation on the waveform.
This modulation traces the projected solar density and gravitational potential along the path as
the Sun passes in front of the neutron star. We calculate how accurately the solar density prole
can be extracted from the lensed GWs using a Fisher analysis. For this purpose, we selected three
promising candidates (the highly spinning pulsars J1022+1001, J1730-2304, and J1745-23) from the
pulsar catalog of the Australia Telescope National Facility. The lensing signature can be measured
with 3 condence when the signal-to-noise ratio (SNR) of the GW detection reaches 100 (f=300Hz)1
over a one-year observation period (where f is the GW frequency). The solar density prole can be
plotted as a function of radius when the SNR improves to & 104.
The physical conditions_in_a_pre_super_star_cluster_molecular_cloud_in_the_an...Sérgio Sacani
The document summarizes a study of an extreme molecular cloud in the Antennae galaxies that has properties consistent with forming a globular cluster. ALMA observations reveal a cloud with a radius of 24 pc and mass greater than 5 million solar masses. While capable of forming a globular cluster, a lack of associated thermal radio emission indicates star formation has not yet begun to alter the environment, suggesting the cloud is in an early stage of evolution. For the cloud to be confined as observed, an external pressure over 10,000 times greater than typical interstellar pressure is required, supporting the theory that high pressures are needed to form globular clusters in extreme environments like mergers.
Detecting a disc bending wave in a barred-spiral galaxy at redshift 4.4Sérgio Sacani
The recent discovery of barred spiral galaxies in the early Universe (z > 2) poses questions of how these structures form and
how they influence galaxy evolution in the early Universe. In this study, we investigate the morphology and kinematics of the
far-infrared (FIR) continuum and [C II] emission in BRI1335-0417 at z ≈ 4.4 from ALMA observations. The variations in
position angle and ellipticity of the isophotes show the characteristic signature of a barred galaxy. The bar, 3.3+0.2 −0.2 kpc long in
radius and bridging the previously identified two-armed spiral, is evident in both [C II] and FIR images, driving the galaxy’s rapid
evolution by channelling gas towards the nucleus. Fourier analysis of the [C II] velocity field reveals an unambiguous kinematic
m = 2 mode with a line-of-sight velocity amplitude of up to ∼30–40 km s−1; a plausible explanation is the disc’s vertical bending
mode triggered by external perturbation, which presumably induced the high star formation rate and the bar/spiral structure. The
bar identified in [C II] and FIR images of the gas-rich disc galaxy ( 70 per cent of the total mass within radius R ≈ 2.2 disc
scale lengths) suggests a new perspective of early bar formation in high redshift gas-rich galaxies – a gravitationally unstable
gas-rich disc creating a star-forming gaseous bar, rather than a stellar bar emerging from a pre-existing stellar disc. This may
explain the prevalent bar-like structures seen in FIR images of high-redshift submillimeter galaxies.
Searching for Anisotropic Stochastic Gravitational-wave Backgrounds with Cons...Sérgio Sacani
Many recent works have shown that the angular resolution of ground-based detectors is too poor to characterize the
anisotropies of the stochastic gravitational-wave background (SGWB). For this reason, we asked ourselves if a
constellation of space-based instruments could be more suitable. We consider the Laser Interferometer Space
Antenna (LISA), a constellation of multiple LISA-like clusters, and the Deci-hertz Interferometer Gravitationalwave Observatory (DECIGO). Specifically, we test whether these detector constellations can probe the anisotropies
of the SGWB. For this scope, we considered the SGWB produced by two astrophysical sources: merging compact
binaries, and a recently proposed scenario for massive black hole seed formation through multiple mergers of
stellar remnants. We find that measuring the angular power spectrum of the SGWB anisotropies is almost
unattainable. However, it turns out that it could be possible to probe the SGWB anisotropies through crosscorrelation with the cosmic microwave background (CMB) fluctuations. In particular, we find that a constellation
of two LISA-like detectors and CMB-S4 can marginally constrain the cross-correlation between the CMB lensing
convergence and the SGWB produced by the black hole seed formation process. Moreover, we find that DECI
Continuum emission from within the plunging region of black hole discsSérgio Sacani
The thermal continuum emission observed from accreting black holes across X-ray bands has the potential to be leveraged as a
powerful probe of the mass and spin of the central black hole. The vast majority of existing ‘continuum fitting’ models neglect
emission sourced at and within the innermost stable circular orbit (ISCO) of the black hole. Numerical simulations, however,
find non-zero emission sourced from these regions. In this work, we extend existing techniques by including the emission
sourced from within the plunging region, utilizing new analytical models that reproduce the properties of numerical accretion
simulations. We show that in general the neglected intra-ISCO emission produces a hot-and-small quasi-blackbody component,
but can also produce a weak power-law tail for more extreme parameter regions. A similar hot-and-small blackbody component
has been added in by hand in an ad hoc manner to previous analyses of X-ray binary spectra. We show that the X-ray spectrum
of MAXI J1820+070 in a soft-state outburst is extremely well described by a full Kerr black hole disc, while conventional
models that neglect intra-ISCO emission are unable to reproduce the data. We believe this represents the first robust detection of
intra-ISCO emission in the literature, and allows additional constraints to be placed on the MAXI J1820 + 070 black hole spin
which must be low a• < 0.5 to allow a detectable intra-ISCO region. Emission from within the ISCO is the dominant emission
component in the MAXI J1820 + 070 spectrum between 6 and 10 keV, highlighting the necessity of including this region. Our
continuum fitting model is made publicly available.
The colision between_the_milky_way_and_andromedaSérgio Sacani
The document summarizes a simulation of the future collision between the Milky Way and Andromeda galaxies. It finds that given current observational constraints on their distance, velocity, and masses:
1) The Milky Way and Andromeda are likely to collide in a few billion years, within the lifetime of the Sun.
2) During the interaction, there is a chance the Sun could be pulled into an extended tidal tail between the galaxies.
3) Eventually, after the merger is complete, the Sun would most likely be scattered to the outer halo of the merged galaxy at a distance over 30 kpc.
The massive relic galaxy NGC 1277 is dark matter deficient From dynamical mod...Sérgio Sacani
According to the Λ cold dark matter (ΛCDM) cosmology, present-day galaxies with stellar masses M? > 1011 M should contain
a sizable fraction of dark matter within their stellar body. Models indicate that in massive early-type galaxies (ETGs) with M? ≈
1.5 × 1011 M, dark matter should account for ∼15% of the dynamical mass within one effective radius (1 Re) and for ∼60% within
5 Re
. Most massive ETGs have been shaped through a two-phase process: the rapid growth of a compact core was followed by the
accretion of an extended envelope through mergers. The exceedingly rare galaxies that have avoided the second phase, the so-called
relic galaxies, are thought to be the frozen remains of the massive ETG population at z & 2. The best relic galaxy candidate discovered
to date is NGC 1277, in the Perseus cluster. We used deep integral field George and Cynthia Mitchel Spectrograph (GCMS) data to
revisit NGC 1277 out to an unprecedented radius of 6 kpc (corresponding to 5 Re). By using Jeans anisotropic modelling, we find
a negligible dark matter fraction within 5 Re (fDM(5 Re) < 0.05; two-sigma confidence level), which is in tension with the ΛCDM
expectation. Since the lack of an extended envelope would reduce dynamical friction and prevent the accretion of an envelope, we
propose that NGC 1277 lost its dark matter very early or that it was dark matter deficient ab initio. We discuss our discovery in the
framework of recent proposals, suggesting that some relic galaxies may result from dark matter stripping as they fell in and interacted
within galaxy clusters. Alternatively, NGC 1277 might have been born in a high-velocity collision of gas-rich proto-galactic fragments,
where dark matter left behind a disc of dissipative baryons. We speculate that the relative velocities of ≈2000 km s−1
required for the
latter process to happen were possible in the progenitors of the present-day rich galaxy clusters.
Kinematics and simulations_of_the_stellar_stream_in_the_halo_of_the_umbrella_...Sérgio Sacani
This document summarizes a study of the stellar stream and substructures around the Umbrella Galaxy (NGC 4651). Deep imaging and spectroscopy were used to characterize the properties and kinematics of the stream. Tracer objects like globular clusters and planetary nebulae were identified and found to delineate a kinematically cold feature in position-velocity space. Dynamical modeling suggests the stream originated from the tidal disruption of a dwarf galaxy on a highly eccentric orbit about 6-10 billion years ago. This work demonstrates the feasibility of using discrete tracers to recover the kinematics and model the dynamics of low surface brightness stellar streams around distant galaxies.
Young remmants of_type_ia_supernovae_and_their_progenitors_a_study_of_snr_g19_03Sérgio Sacani
Type Ia supernovae, with their remarkably homogeneous light curves and spectra, have been used as
standardizable candles to measure the accelerating expansion of the Universe. Yet, their progenitors
remain elusive. Common explanations invoke a degenerate star (white dwarf) which explodes upon
reaching close to the Chandrasekhar limit, by either steadily accreting mass from a companion star
or violently merging with another degenerate star. We show that circumstellar interaction in young
Galactic supernova remnants can be used to distinguish between these single and double degenerate
progenitor scenarios. Here we propose a new diagnostic, the Surface Brightness Index, which can
be computed from theory and compared with Chandra and VLA observations. We use this method
to demonstrate that a double degenerate progenitor can explain the decades-long
ux rise and size
increase of the youngest known Galactic SNR G1.9+0.3. We disfavor a single degenerate scenario.
We attribute the observed properties to the interaction between a steep ejecta prole and a constant
density environment. We suggest using the upgraded VLA to detect circumstellar interaction in
the remnants of historical Type Ia supernovae in the Local Group of galaxies. This may settle the
long-standing debate over their progenitors.
Subject headings: ISM: supernova remnants | radio continuum: general | X-rays: general | bi-
naries: general | circumstellar matter | supernovae: general | ISM: individual
objects(SNR G1.9+0.3)
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
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Jet reorientation in central galaxies of clusters and groups: insights from V...Sérgio Sacani
Recent observations of galaxy clusters and groups with misalignments between their central AGN jets
and X-ray cavities, or with multiple misaligned cavities, have raised concerns about the jet – bubble
connection in cooling cores, and the processes responsible for jet realignment. To investigate the
frequency and causes of such misalignments, we construct a sample of 16 cool core galaxy clusters and
groups. Using VLBA radio data we measure the parsec-scale position angle of the jets, and compare
it with the position angle of the X-ray cavities detected in Chandra data. Using the overall sample
and selected subsets, we consistently find that there is a 30% – 38% chance to find a misalignment
larger than ∆Ψ = 45◦ when observing a cluster/group with a detected jet and at least one cavity. We
determine that projection may account for an apparently large ∆Ψ only in a fraction of objects (∼35%),
and given that gas dynamical disturbances (as sloshing) are found in both aligned and misaligned
systems, we exclude environmental perturbation as the main driver of cavity – jet misalignment.
Moreover, we find that large misalignments (up to ∼ 90◦
) are favored over smaller ones (45◦ ≤ ∆Ψ ≤
70◦
), and that the change in jet direction can occur on timescales between one and a few tens of Myr.
We conclude that misalignments are more likely related to actual reorientation of the jet axis, and we
discuss several engine-based mechanisms that may cause these dramatic changes.
Exploring Proxies for the Supermassive Black Hole Mass Function: Implications...Sérgio Sacani
Supermassive black holes (SMBHs) reside at the center of every massive galaxy in the local universe with masses
that closely correlate with observations of their host galaxy, implying a connected evolutionary history. The
population of binary SMBHs, which form following galaxy mergers, is expected to produce a gravitational-wave
background (GWB) detectable by pulsar timing arrays (PTAs). PTAs are starting to see hints of what may be a
GWB, and the amplitude of the emerging signal is toward the higher end of model predictions. Simulated
populations of binary SMBHs can be constructed from observations of galaxies and are used to make predictions
about the nature of the GWB. The greatest source of uncertainty in these observation-based models comes from the
inference of the SMBH mass function, which is derived from observed host galaxy properties. In this paper, I
undertake a new approach for inferring the SMBH mass function, starting from a velocity dispersion function
rather than a galaxy stellar mass function. I argue that this method allows for a more direct inference by relying on
a larger suite of individual galaxy observations as well as relying on a more “fundamental” SMBH mass relation. I
find that the resulting binary SMBH population contains more massive systems at higher redshifts than previous
models. Additionally, I explore the implications for the detection of individually resolvable sources in PTA data.
The hazardous km-sized NEOs of the next thousands of yearsSérgio Sacani
This document discusses methods for assessing the long-term impact risk of km-sized near-Earth objects (NEOs) over thousands of years. It analyzes the evolution of the Minimum Orbit Intersection Distance (MOID) between NEOs and Earth to identify objects that remain in close proximity for extended periods. It then estimates the probability of a deep Earth encounter during these low-MOID periods based on the growth of orbital uncertainties over time. This allows the authors to rank km-sized NEOs by their long-term impact hazard and identify targets that warrant further observation and analysis.
A vlt flames_survey_for_massive_binaries_in_westerlund_1Sérgio Sacani
1) The authors conducted a radial velocity survey of stars in the young massive cluster Westerlund 1 to search for a potential pre-supernova companion to the magnetar CXO J1647-10.2-455216 located within the cluster.
2) They identified a candidate star, Wd1-5, that has anomalous velocities compared to other stars in the cluster, suggesting it was impacted by the supernova that created the magnetar.
3) Analysis of Wd1-5 found evidence of chemical enrichment that is difficult to explain by single star evolution, but could be explained if Wd1-5 was once part of a close binary system where it accreted material from
A Neutron Star with a Massive Progenitor in Westerlund 1GOASA
1) The authors conducted a radial velocity survey of stars in the young massive cluster Westerlund 1 to search for a potential pre-supernova companion to the magnetar CXO J1647-10.2-455216 located within the cluster.
2) They identified a candidate star, Wd1-5, that has anomalous velocities compared to other stars in the cluster, suggesting it was impacted by the supernova of the magnetar's progenitor star.
3) Analysis of Wd1-5 found evidence of chemical enrichment that is difficult to explain by single star evolution, suggesting it was part of a binary system where it accreted material from the magnetar's progenitor prior to its
AT2023fhn (the Finch): a Luminous Fast Blue Optical Transient at a large offs...Sérgio Sacani
Luminous Fast Blue Optical Transients (LFBOTs) - the prototypical example being AT 2018cow - are a rare class of events
whose origins are poorly understood. They are characterised by rapid evolution, featureless blue spectra at early times, and
luminous X-ray and radio emission. LFBOTs thus far have been found exclusively at small projected offsets from star-forming
host galaxies. We present Hubble Space Telescope, Gemini, Chandra and Very Large Array observations of a new LFBOT,
AT 2023fhn. The Hubble Space Telescope data reveal a large offset (> 3.5 half-light radii) from the two closest galaxies, both
at redshift 𝑧 ∼ 0.24. The location of AT 2023fhn is in stark contrast with previous events, and demonstrates that LFBOTs can
occur in a range of galactic environments.
Formation of low mass protostars and their circumstellar disksSérgio Sacani
Understanding circumstellar disks is of prime importance in astrophysics, however, their birth process remains poorly constrained due to observational and numerical challenges. Recent numerical works have shown that the small-scale physics, often wrapped into a sub-grid model, play a crucial role in disk formation and evolution. This calls for a combined approach in which both the protostar and circumstellar disk are studied in concert. Aims. We aim to elucidate the small scale physics and constrain sub-grid parameters commonly chosen in the literature by resolving the star-disk interaction. Methods. We carry out a set of very high resolution 3D radiative-hydrodynamics simulations that self-consistently describe the collapse of a turbulent dense molecular cloud core to stellar densities. We study the birth of the protostar, the circumstellar disk, and its early evolution (< 6 yr after protostellar formation). Results. Following the second gravitational collapse, the nascent protostar quickly reaches breakup velocity and sheds its surface material, thus forming a hot (∼ 103 K), dense, and highly flared circumstellar disk. The protostar is embedded within the disk, such that material can flow without crossing any shock fronts. The circumstellar disk mass quickly exceeds that of the protostar, and its kinematics are dominated by self-gravity. Accretion onto the disk is highly anisotropic, and accretion onto the protostar mainly occurs through material that slides on the disk surface. The polar mass flux is negligible in comparison. The radiative behavior also displays a strong anisotropy, as the polar accretion shock is shown to be supercritical whereas its equatorial counterpart is subcritical. We also f ind a remarkable convergence of our results with respect to initial conditions. Conclusions. These results reveal the structure and kinematics in the smallest spatial scales relevant to protostellar and circumstellar disk evolution. They can be used to describe accretion onto regions commonly described by sub-grid models in simulations studying larger scale physics.
The Sparkler: Evolved High-redshift Globular Cluster Candidates Captured by JWSTSérgio Sacani
This document discusses compact red sources detected around a strongly lensed galaxy ("the Sparkler") at a redshift of 1.378 using JWST data. Photometry and morphological fits of the sources suggest they are spatially unresolved, very red, and consistent with old stellar populations. Spectroscopy shows emission from the galaxy but no signs of star formation in the red sources. The sources are most likely evolved globular clusters dating back to formation redshifts between 7-11, corresponding to ages of 3.9-4.1 billion years at the time of observation. If confirmed, these would be the first observed globular clusters at high redshift, opening a window into early globular cluster formation in the first billion years of
Is Betelgeuse Really Rotating? Synthetic ALMA Observations of Large-scale Con...Sérgio Sacani
The evolved stages of massive stars are poorly understood, but invaluable constraints can be derived from spatially resolved observations of nearby red supergiants, such as Betelgeuse. Atacama Large Millimeter/submillimeter Array (ALMA) observations of Betelgeuse showing a dipolar velocity field have been interpreted as evidence for a projected rotation rate of about 5 km s−1. This is 2 orders of magnitude larger than predicted by single-star evolution, which led to suggestions that Betelgeuse is a binary merger. We propose instead that large-scale convective motions can mimic rotation, especially if they are only partially resolved. We support this claim with 3D CO5BOLDsimulations of nonrotating red supergiants that we postprocessed to predict ALMA images and SiO spectra. We show that our synthetic radial velocity maps have a 90% chance of being falsely interpreted as evidence for a projected rotation rate of 2 km s−1 or larger for our fiducial simulation. We conclude that we need at least another ALMA observation to firmly establish whether Betelgeuse is indeed rapidly rotating. Such observations would also provide insight into the role of angular momentum and binary interaction in the late evolutionary stages. The data will further probe the structure and complex physical processes in the atmospheres of red supergiants, which are immediate progenitors of supernovae and are believed to be essential in the formation of gravitational-wave sources.
Exploring the nature and synchronicity of early cluster formation in the Larg...Sérgio Sacani
We analyse Hubble Space Telescope observations of six globular clusters in the Large Magel- lanic Cloud (LMC) from programme GO-14164 in Cycle 23. These are the deepest available observations of the LMC globular cluster population; their uniformity facilitates a precise comparison with globular clusters in the Milky Way. Measuring the magnitude of the main- sequence turn-off point relative to template Galactic globular clusters allows the relative ages of the clusters to be determined with a mean precision of 8.4 per cent, and down to 6 per cent for individual objects. We find that the mean age of our LMC cluster ensemble is identical to the mean age of the oldest metal-poor clusters in the Milky Way halo to 0.2 ± 0.4 Gyr. This provides the most sensitive test to date of the synchronicity of the earliest epoch of globular cluster formation in two independent galaxies. Horizontal branch magnitudes and subdwarf fitting to the main sequence allow us to determine distance estimates for each cluster and examine their geometric distribution in the LMC. Using two different methods, we find an average distance to the LMC of 18.52 ± 0.05.
PROBING THE SOLAR INTERIOR WITH LENSED GRAVITATIONAL WAVES FROM KNOWN PULSARSSérgio Sacani
When gravitational waves (GWs) from a spinning neutron star arrive from behind the Sun, they are
subjected to gravitational lensing that imprints a frequency-dependent modulation on the waveform.
This modulation traces the projected solar density and gravitational potential along the path as
the Sun passes in front of the neutron star. We calculate how accurately the solar density prole
can be extracted from the lensed GWs using a Fisher analysis. For this purpose, we selected three
promising candidates (the highly spinning pulsars J1022+1001, J1730-2304, and J1745-23) from the
pulsar catalog of the Australia Telescope National Facility. The lensing signature can be measured
with 3 condence when the signal-to-noise ratio (SNR) of the GW detection reaches 100 (f=300Hz)1
over a one-year observation period (where f is the GW frequency). The solar density prole can be
plotted as a function of radius when the SNR improves to & 104.
The physical conditions_in_a_pre_super_star_cluster_molecular_cloud_in_the_an...Sérgio Sacani
The document summarizes a study of an extreme molecular cloud in the Antennae galaxies that has properties consistent with forming a globular cluster. ALMA observations reveal a cloud with a radius of 24 pc and mass greater than 5 million solar masses. While capable of forming a globular cluster, a lack of associated thermal radio emission indicates star formation has not yet begun to alter the environment, suggesting the cloud is in an early stage of evolution. For the cloud to be confined as observed, an external pressure over 10,000 times greater than typical interstellar pressure is required, supporting the theory that high pressures are needed to form globular clusters in extreme environments like mergers.
Detecting a disc bending wave in a barred-spiral galaxy at redshift 4.4Sérgio Sacani
The recent discovery of barred spiral galaxies in the early Universe (z > 2) poses questions of how these structures form and
how they influence galaxy evolution in the early Universe. In this study, we investigate the morphology and kinematics of the
far-infrared (FIR) continuum and [C II] emission in BRI1335-0417 at z ≈ 4.4 from ALMA observations. The variations in
position angle and ellipticity of the isophotes show the characteristic signature of a barred galaxy. The bar, 3.3+0.2 −0.2 kpc long in
radius and bridging the previously identified two-armed spiral, is evident in both [C II] and FIR images, driving the galaxy’s rapid
evolution by channelling gas towards the nucleus. Fourier analysis of the [C II] velocity field reveals an unambiguous kinematic
m = 2 mode with a line-of-sight velocity amplitude of up to ∼30–40 km s−1; a plausible explanation is the disc’s vertical bending
mode triggered by external perturbation, which presumably induced the high star formation rate and the bar/spiral structure. The
bar identified in [C II] and FIR images of the gas-rich disc galaxy ( 70 per cent of the total mass within radius R ≈ 2.2 disc
scale lengths) suggests a new perspective of early bar formation in high redshift gas-rich galaxies – a gravitationally unstable
gas-rich disc creating a star-forming gaseous bar, rather than a stellar bar emerging from a pre-existing stellar disc. This may
explain the prevalent bar-like structures seen in FIR images of high-redshift submillimeter galaxies.
Searching for Anisotropic Stochastic Gravitational-wave Backgrounds with Cons...Sérgio Sacani
Many recent works have shown that the angular resolution of ground-based detectors is too poor to characterize the
anisotropies of the stochastic gravitational-wave background (SGWB). For this reason, we asked ourselves if a
constellation of space-based instruments could be more suitable. We consider the Laser Interferometer Space
Antenna (LISA), a constellation of multiple LISA-like clusters, and the Deci-hertz Interferometer Gravitationalwave Observatory (DECIGO). Specifically, we test whether these detector constellations can probe the anisotropies
of the SGWB. For this scope, we considered the SGWB produced by two astrophysical sources: merging compact
binaries, and a recently proposed scenario for massive black hole seed formation through multiple mergers of
stellar remnants. We find that measuring the angular power spectrum of the SGWB anisotropies is almost
unattainable. However, it turns out that it could be possible to probe the SGWB anisotropies through crosscorrelation with the cosmic microwave background (CMB) fluctuations. In particular, we find that a constellation
of two LISA-like detectors and CMB-S4 can marginally constrain the cross-correlation between the CMB lensing
convergence and the SGWB produced by the black hole seed formation process. Moreover, we find that DECI
Continuum emission from within the plunging region of black hole discsSérgio Sacani
The thermal continuum emission observed from accreting black holes across X-ray bands has the potential to be leveraged as a
powerful probe of the mass and spin of the central black hole. The vast majority of existing ‘continuum fitting’ models neglect
emission sourced at and within the innermost stable circular orbit (ISCO) of the black hole. Numerical simulations, however,
find non-zero emission sourced from these regions. In this work, we extend existing techniques by including the emission
sourced from within the plunging region, utilizing new analytical models that reproduce the properties of numerical accretion
simulations. We show that in general the neglected intra-ISCO emission produces a hot-and-small quasi-blackbody component,
but can also produce a weak power-law tail for more extreme parameter regions. A similar hot-and-small blackbody component
has been added in by hand in an ad hoc manner to previous analyses of X-ray binary spectra. We show that the X-ray spectrum
of MAXI J1820+070 in a soft-state outburst is extremely well described by a full Kerr black hole disc, while conventional
models that neglect intra-ISCO emission are unable to reproduce the data. We believe this represents the first robust detection of
intra-ISCO emission in the literature, and allows additional constraints to be placed on the MAXI J1820 + 070 black hole spin
which must be low a• < 0.5 to allow a detectable intra-ISCO region. Emission from within the ISCO is the dominant emission
component in the MAXI J1820 + 070 spectrum between 6 and 10 keV, highlighting the necessity of including this region. Our
continuum fitting model is made publicly available.
The colision between_the_milky_way_and_andromedaSérgio Sacani
The document summarizes a simulation of the future collision between the Milky Way and Andromeda galaxies. It finds that given current observational constraints on their distance, velocity, and masses:
1) The Milky Way and Andromeda are likely to collide in a few billion years, within the lifetime of the Sun.
2) During the interaction, there is a chance the Sun could be pulled into an extended tidal tail between the galaxies.
3) Eventually, after the merger is complete, the Sun would most likely be scattered to the outer halo of the merged galaxy at a distance over 30 kpc.
The massive relic galaxy NGC 1277 is dark matter deficient From dynamical mod...Sérgio Sacani
According to the Λ cold dark matter (ΛCDM) cosmology, present-day galaxies with stellar masses M? > 1011 M should contain
a sizable fraction of dark matter within their stellar body. Models indicate that in massive early-type galaxies (ETGs) with M? ≈
1.5 × 1011 M, dark matter should account for ∼15% of the dynamical mass within one effective radius (1 Re) and for ∼60% within
5 Re
. Most massive ETGs have been shaped through a two-phase process: the rapid growth of a compact core was followed by the
accretion of an extended envelope through mergers. The exceedingly rare galaxies that have avoided the second phase, the so-called
relic galaxies, are thought to be the frozen remains of the massive ETG population at z & 2. The best relic galaxy candidate discovered
to date is NGC 1277, in the Perseus cluster. We used deep integral field George and Cynthia Mitchel Spectrograph (GCMS) data to
revisit NGC 1277 out to an unprecedented radius of 6 kpc (corresponding to 5 Re). By using Jeans anisotropic modelling, we find
a negligible dark matter fraction within 5 Re (fDM(5 Re) < 0.05; two-sigma confidence level), which is in tension with the ΛCDM
expectation. Since the lack of an extended envelope would reduce dynamical friction and prevent the accretion of an envelope, we
propose that NGC 1277 lost its dark matter very early or that it was dark matter deficient ab initio. We discuss our discovery in the
framework of recent proposals, suggesting that some relic galaxies may result from dark matter stripping as they fell in and interacted
within galaxy clusters. Alternatively, NGC 1277 might have been born in a high-velocity collision of gas-rich proto-galactic fragments,
where dark matter left behind a disc of dissipative baryons. We speculate that the relative velocities of ≈2000 km s−1
required for the
latter process to happen were possible in the progenitors of the present-day rich galaxy clusters.
Kinematics and simulations_of_the_stellar_stream_in_the_halo_of_the_umbrella_...Sérgio Sacani
This document summarizes a study of the stellar stream and substructures around the Umbrella Galaxy (NGC 4651). Deep imaging and spectroscopy were used to characterize the properties and kinematics of the stream. Tracer objects like globular clusters and planetary nebulae were identified and found to delineate a kinematically cold feature in position-velocity space. Dynamical modeling suggests the stream originated from the tidal disruption of a dwarf galaxy on a highly eccentric orbit about 6-10 billion years ago. This work demonstrates the feasibility of using discrete tracers to recover the kinematics and model the dynamics of low surface brightness stellar streams around distant galaxies.
Young remmants of_type_ia_supernovae_and_their_progenitors_a_study_of_snr_g19_03Sérgio Sacani
Type Ia supernovae, with their remarkably homogeneous light curves and spectra, have been used as
standardizable candles to measure the accelerating expansion of the Universe. Yet, their progenitors
remain elusive. Common explanations invoke a degenerate star (white dwarf) which explodes upon
reaching close to the Chandrasekhar limit, by either steadily accreting mass from a companion star
or violently merging with another degenerate star. We show that circumstellar interaction in young
Galactic supernova remnants can be used to distinguish between these single and double degenerate
progenitor scenarios. Here we propose a new diagnostic, the Surface Brightness Index, which can
be computed from theory and compared with Chandra and VLA observations. We use this method
to demonstrate that a double degenerate progenitor can explain the decades-long
ux rise and size
increase of the youngest known Galactic SNR G1.9+0.3. We disfavor a single degenerate scenario.
We attribute the observed properties to the interaction between a steep ejecta prole and a constant
density environment. We suggest using the upgraded VLA to detect circumstellar interaction in
the remnants of historical Type Ia supernovae in the Local Group of galaxies. This may settle the
long-standing debate over their progenitors.
Subject headings: ISM: supernova remnants | radio continuum: general | X-rays: general | bi-
naries: general | circumstellar matter | supernovae: general | ISM: individual
objects(SNR G1.9+0.3)
Ähnlich wie A Comprehensive Theory for Neutron Star and Black Hole Kicks and Induced Spins (20)
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Gliese 12 b: A Temperate Earth-sized Planet at 12 pc Ideal for Atmospheric Tr...Sérgio Sacani
Recent discoveries of Earth-sized planets transiting nearby M dwarfs have made it possible to characterize the
atmospheres of terrestrial planets via follow-up spectroscopic observations. However, the number of such planets
receiving low insolation is still small, limiting our ability to understand the diversity of the atmospheric
composition and climates of temperate terrestrial planets. We report the discovery of an Earth-sized planet
transiting the nearby (12 pc) inactive M3.0 dwarf Gliese 12 (TOI-6251) with an orbital period (Porb) of 12.76 days.
The planet, Gliese 12 b, was initially identified as a candidate with an ambiguous Porb from TESS data. We
confirmed the transit signal and Porb using ground-based photometry with MuSCAT2 and MuSCAT3, and
validated the planetary nature of the signal using high-resolution images from Gemini/NIRI and Keck/NIRC2 as
well as radial velocity (RV) measurements from the InfraRed Doppler instrument on the Subaru 8.2 m telescope
and from CARMENES on the CAHA 3.5 m telescope. X-ray observations with XMM-Newton showed the host
star is inactive, with an X-ray-to-bolometric luminosity ratio of log 5.7 L L X bol » - . Joint analysis of the light
curves and RV measurements revealed that Gliese 12 b has a radius of 0.96 ± 0.05 R⊕,a3σ mass upper limit of
3.9 M⊕, and an equilibrium temperature of 315 ± 6 K assuming zero albedo. The transmission spectroscopy metric
(TSM) value of Gliese 12 b is close to the TSM values of the TRAPPIST-1 planets, adding Gliese 12 b to the small
list of potentially terrestrial, temperate planets amenable to atmospheric characterization with JWST.
Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...Sérgio Sacani
We report on the discovery of Gliese 12 b, the nearest transiting temperate, Earth-sized planet found to date. Gliese 12 is a
bright (V = 12.6 mag, K = 7.8 mag) metal-poor M4V star only 12.162 ± 0.005 pc away from the Solar system with one of the
lowest stellar activity levels known for M-dwarfs. A planet candidate was detected by TESS based on only 3 transits in sectors
42, 43, and 57, with an ambiguity in the orbital period due to observational gaps. We performed follow-up transit observations
with CHEOPS and ground-based photometry with MINERVA-Australis, SPECULOOS, and Purple Mountain Observatory,
as well as further TESS observations in sector 70. We statistically validate Gliese 12 b as a planet with an orbital period of
12.76144 ± 0.00006 d and a radius of 1.0 ± 0.1 R⊕, resulting in an equilibrium temperature of ∼315 K. Gliese 12 b has excellent
future prospects for precise mass measurement, which may inform how planetary internal structure is affected by the stellar
compositional environment. Gliese 12 b also represents one of the best targets to study whether Earth-like planets orbiting cool
stars can retain their atmospheres, a crucial step to advance our understanding of habitability on Earth and across the galaxy.
The importance of continents, oceans and plate tectonics for the evolution of...Sérgio Sacani
Within the uncertainties of involved astronomical and biological parameters, the Drake Equation
typically predicts that there should be many exoplanets in our galaxy hosting active, communicative
civilizations (ACCs). These optimistic calculations are however not supported by evidence, which is
often referred to as the Fermi Paradox. Here, we elaborate on this long-standing enigma by showing
the importance of planetary tectonic style for biological evolution. We summarize growing evidence
that a prolonged transition from Mesoproterozoic active single lid tectonics (1.6 to 1.0 Ga) to modern
plate tectonics occurred in the Neoproterozoic Era (1.0 to 0.541 Ga), which dramatically accelerated
emergence and evolution of complex species. We further suggest that both continents and oceans
are required for ACCs because early evolution of simple life must happen in water but late evolution
of advanced life capable of creating technology must happen on land. We resolve the Fermi Paradox
(1) by adding two additional terms to the Drake Equation: foc
(the fraction of habitable exoplanets
with significant continents and oceans) and fpt
(the fraction of habitable exoplanets with significant
continents and oceans that have had plate tectonics operating for at least 0.5 Ga); and (2) by
demonstrating that the product of foc
and fpt
is very small (< 0.00003–0.002). We propose that the lack
of evidence for ACCs reflects the scarcity of long-lived plate tectonics and/or continents and oceans on
exoplanets with primitive life.
A Giant Impact Origin for the First Subduction on EarthSérgio Sacani
Hadean zircons provide a potential record of Earth's earliest subduction 4.3 billion years ago. Itremains enigmatic how subduction could be initiated so soon after the presumably Moon‐forming giant impact(MGI). Earlier studies found an increase in Earth's core‐mantle boundary (CMB) temperature due to theaccumulation of the impactor's core, and our recent work shows Earth's lower mantle remains largely solid, withsome of the impactor's mantle potentially surviving as the large low‐shear velocity provinces (LLSVPs). Here,we show that a hot post‐impact CMB drives the initiation of strong mantle plumes that can induce subductioninitiation ∼200 Myr after the MGI. 2D and 3D thermomechanical computations show that a high CMBtemperature is the primary factor triggering early subduction, with enrichment of heat‐producing elements inLLSVPs as another potential factor. The models link the earliest subduction to the MGI with implications forunderstanding the diverse tectonic regimes of rocky planets.
Climate extremes likely to drive land mammal extinction during next supercont...Sérgio Sacani
Mammals have dominated Earth for approximately 55 Myr thanks to their
adaptations and resilience to warming and cooling during the Cenozoic. All
life will eventually perish in a runaway greenhouse once absorbed solar
radiation exceeds the emission of thermal radiation in several billions of
years. However, conditions rendering the Earth naturally inhospitable to
mammals may develop sooner because of long-term processes linked to
plate tectonics (short-term perturbations are not considered here). In
~250 Myr, all continents will converge to form Earth’s next supercontinent,
Pangea Ultima. A natural consequence of the creation and decay of Pangea
Ultima will be extremes in pCO2 due to changes in volcanic rifting and
outgassing. Here we show that increased pCO2, solar energy (F⨀;
approximately +2.5% W m−2 greater than today) and continentality (larger
range in temperatures away from the ocean) lead to increasing warming
hostile to mammalian life. We assess their impact on mammalian
physiological limits (dry bulb, wet bulb and Humidex heat stress indicators)
as well as a planetary habitability index. Given mammals’ continued survival,
predicted background pCO2 levels of 410–816 ppm combined with increased
F⨀ will probably lead to a climate tipping point and their mass extinction.
The results also highlight how global landmass configuration, pCO2 and F⨀
play a critical role in planetary habitability.
Constraints on Neutrino Natal Kicks from Black-Hole Binary VFTS 243Sérgio Sacani
The recently reported observation of VFTS 243 is the first example of a massive black-hole binary
system with negligible binary interaction following black-hole formation. The black-hole mass (≈10M⊙)
and near-circular orbit (e ≈ 0.02) of VFTS 243 suggest that the progenitor star experienced complete
collapse, with energy-momentum being lost predominantly through neutrinos. VFTS 243 enables us to
constrain the natal kick and neutrino-emission asymmetry during black-hole formation. At 68% confidence
level, the natal kick velocity (mass decrement) is ≲10 km=s (≲1.0M⊙), with a full probability distribution
that peaks when ≈0.3M⊙ were ejected, presumably in neutrinos, and the black hole experienced a natal
kick of 4 km=s. The neutrino-emission asymmetry is ≲4%, with best fit values of ∼0–0.2%. Such a small
neutrino natal kick accompanying black-hole formation is in agreement with theoretical predictions.
Detectability of Solar Panels as a TechnosignatureSérgio Sacani
In this work, we assess the potential detectability of solar panels made of silicon on an Earth-like
exoplanet as a potential technosignature. Silicon-based photovoltaic cells have high reflectance in the
UV-VIS and in the near-IR, within the wavelength range of a space-based flagship mission concept
like the Habitable Worlds Observatory (HWO). Assuming that only solar energy is used to provide
the 2022 human energy needs with a land cover of ∼ 2.4%, and projecting the future energy demand
assuming various growth-rate scenarios, we assess the detectability with an 8 m HWO-like telescope.
Assuming the most favorable viewing orientation, and focusing on the strong absorption edge in the
ultraviolet-to-visible (0.34 − 0.52 µm), we find that several 100s of hours of observation time is needed
to reach a SNR of 5 for an Earth-like planet around a Sun-like star at 10pc, even with a solar panel
coverage of ∼ 23% land coverage of a future Earth. We discuss the necessity of concepts like Kardeshev
Type I/II civilizations and Dyson spheres, which would aim to harness vast amounts of energy. Even
with much larger populations than today, the total energy use of human civilization would be orders of
magnitude below the threshold for causing direct thermal heating or reaching the scale of a Kardashev
Type I civilization. Any extraterrrestrial civilization that likewise achieves sustainable population
levels may also find a limit on its need to expand, which suggests that a galaxy-spanning civilization
as imagined in the Fermi paradox may not exist.
The solar dynamo begins near the surfaceSérgio Sacani
The magnetic dynamo cycle of the Sun features a distinct pattern: a propagating
region of sunspot emergence appears around 30° latitude and vanishes near the
equator every 11 years (ref. 1). Moreover, longitudinal flows called torsional oscillations
closely shadow sunspot migration, undoubtedly sharing a common cause2. Contrary
to theories suggesting deep origins of these phenomena, helioseismology pinpoints
low-latitude torsional oscillations to the outer 5–10% of the Sun, the near-surface
shear layer3,4. Within this zone, inwardly increasing differential rotation coupled with
a poloidal magnetic field strongly implicates the magneto-rotational instability5,6,
prominent in accretion-disk theory and observed in laboratory experiments7.
Together, these two facts prompt the general question: whether the solar dynamo is
possibly a near-surface instability. Here we report strong affirmative evidence in stark
contrast to traditional models8 focusing on the deeper tachocline. Simple analytic
estimates show that the near-surface magneto-rotational instability better explains
the spatiotemporal scales of the torsional oscillations and inferred subsurface
magnetic field amplitudes9. State-of-the-art numerical simulations corroborate these
estimates and reproduce hemispherical magnetic current helicity laws10. The dynamo
resulting from a well-understood near-surface phenomenon improves prospects
for accurate predictions of full magnetic cycles and space weather, affecting the
electromagnetic infrastructure of Earth.
Extensive Pollution of Uranus and Neptune’s Atmospheres by Upsweep of Icy Mat...Sérgio Sacani
In the Nice model of solar system formation, Uranus and Neptune undergo an orbital upheaval,
sweeping through a planetesimal disk. The region of the disk from which material is accreted by
the ice giants during this phase of their evolution has not previously been identified. We perform
direct N-body orbital simulations of the four giant planets to determine the amount and origin of solid
accretion during this orbital upheaval. We find that the ice giants undergo an extreme bombardment
event, with collision rates as much as ∼3 per hour assuming km-sized planetesimals, increasing the
total planet mass by up to ∼0.35%. In all cases, the initially outermost ice giant experiences the
largest total enhancement. We determine that for some plausible planetesimal properties, the resulting
atmospheric enrichment could potentially produce sufficient latent heat to alter the planetary cooling
timescale according to existing models. Our findings suggest that substantial accretion during this
phase of planetary evolution may have been sufficient to impact the atmospheric composition and
thermal evolution of the ice giants, motivating future work on the fate of deposited solid material.
Exomoons & Exorings with the Habitable Worlds Observatory I: On the Detection...Sérgio Sacani
The highest priority recommendation of the Astro2020 Decadal Survey for space-based astronomy
was the construction of an observatory capable of characterizing habitable worlds. In this paper series
we explore the detectability of and interference from exomoons and exorings serendipitously observed
with the proposed Habitable Worlds Observatory (HWO) as it seeks to characterize exoplanets, starting
in this manuscript with Earth-Moon analog mutual events. Unlike transits, which only occur in systems
viewed near edge-on, shadow (i.e., solar eclipse) and lunar eclipse mutual events occur in almost every
star-planet-moon system. The cadence of these events can vary widely from ∼yearly to multiple events
per day, as was the case in our younger Earth-Moon system. Leveraging previous space-based (EPOXI)
lightcurves of a Moon transit and performance predictions from the LUVOIR-B concept, we derive
the detectability of Moon analogs with HWO. We determine that Earth-Moon analogs are detectable
with observation of ∼2-20 mutual events for systems within 10 pc, and larger moons should remain
detectable out to 20 pc. We explore the extent to which exomoon mutual events can mimic planet
features and weather. We find that HWO wavelength coverage in the near-IR, specifically in the 1.4 µm
water band where large moons can outshine their host planet, will aid in differentiating exomoon signals
from exoplanet variability. Finally, we predict that exomoons formed through collision processes akin
to our Moon are more likely to be detected in younger systems, where shorter orbital periods and
favorable geometry enhance the probability and frequency of mutual events.
Emergent ribozyme behaviors in oxychlorine brines indicate a unique niche for...Sérgio Sacani
Mars is a particularly attractive candidate among known astronomical objects
to potentially host life. Results from space exploration missions have provided
insights into Martian geochemistry that indicate oxychlorine species, particularly perchlorate, are ubiquitous features of the Martian geochemical landscape. Perchlorate presents potential obstacles for known forms of life due to
its toxicity. However, it can also provide potential benefits, such as producing
brines by deliquescence, like those thought to exist on present-day Mars. Here
we show perchlorate brines support folding and catalysis of functional RNAs,
while inactivating representative protein enzymes. Additionally, we show
perchlorate and other oxychlorine species enable ribozyme functions,
including homeostasis-like regulatory behavior and ribozyme-catalyzed
chlorination of organic molecules. We suggest nucleic acids are uniquely wellsuited to hypersaline Martian environments. Furthermore, Martian near- or
subsurface oxychlorine brines, and brines found in potential lifeforms, could
provide a unique niche for biomolecular evolution.
WASP-69b’s Escaping Envelope Is Confined to a Tail Extending at Least 7 RpSérgio Sacani
Studying the escaping atmospheres of highly irradiated exoplanets is critical for understanding the physical
mechanisms that shape the demographics of close-in planets. A number of planetary outflows have been observed
as excess H/He absorption during/after transit. Such an outflow has been observed for WASP-69b by multiple
groups that disagree on the geometry and velocity structure of the outflow. Here, we report the detection of this
planet’s outflow using Keck/NIRSPEC for the first time. We observed the outflow 1.28 hr after egress until the
target set, demonstrating the outflow extends at least 5.8 × 105 km or 7.5 Rp This detection is significantly longer
than previous observations, which report an outflow extending ∼2.2 planet radii just 1 yr prior. The outflow is
blueshifted by −23 km s−1 in the planetary rest frame. We estimate a current mass-loss rate of 1 M⊕ Gyr−1
. Our
observations are most consistent with an outflow that is strongly sculpted by ram pressure from the stellar wind.
However, potential variability in the outflow could be due to time-varying interactions with the stellar wind or
differences in instrumental precision.
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
Phenomics assisted breeding in crop improvementIshaGoswami9
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
Immersive Learning That Works: Research Grounding and Paths ForwardLeonel Morgado
We will metaverse into the essence of immersive learning, into its three dimensions and conceptual models. This approach encompasses elements from teaching methodologies to social involvement, through organizational concerns and technologies. Challenging the perception of learning as knowledge transfer, we introduce a 'Uses, Practices & Strategies' model operationalized by the 'Immersive Learning Brain' and ‘Immersion Cube’ frameworks. This approach offers a comprehensive guide through the intricacies of immersive educational experiences and spotlighting research frontiers, along the immersion dimensions of system, narrative, and agency. Our discourse extends to stakeholders beyond the academic sphere, addressing the interests of technologists, instructional designers, and policymakers. We span various contexts, from formal education to organizational transformation to the new horizon of an AI-pervasive society. This keynote aims to unite the iLRN community in a collaborative journey towards a future where immersive learning research and practice coalesce, paving the way for innovative educational research and practice landscapes.
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...Advanced-Concepts-Team
Presentation in the Science Coffee of the Advanced Concepts Team of the European Space Agency on the 07.06.2024.
Speaker: Diego Blas (IFAE/ICREA)
Title: Gravitational wave detection with orbital motion of Moon and artificial
Abstract:
In this talk I will describe some recent ideas to find gravitational waves from supermassive black holes or of primordial origin by studying their secular effect on the orbital motion of the Moon or satellites that are laser ranged.
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...AbdullaAlAsif1
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
A Comprehensive Theory for Neutron Star and Black Hole Kicks and Induced Spins
1. Draft version November 22, 2023
Typeset using L
A
TEX default style in AASTeX631
A Comprehensive Theory for Neutron Star and Black Hole Kicks and Induced Spins
Adam Burrows ,1
Tianshu Wang ,2
David Vartanyan ,3
and Matthew S.B. Coleman 4
1Department of Astrophysical Sciences, Princeton University, Princeton NJ 08544 and the Institute for Advanced Study, 1 Einstein
Drive, Princeton NJ 08540
2Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544
3Carnegie Observatories, 813 Santa Barbara St., Pasadena, CA 91101
4Department of Physics and Engineering Physics, Stevens Institute of Technology, Hoboken, NJ, 07030
(Dated: Accepted XXX. Received YYY)
ABSTRACT
Using twenty long-term 3D core-collapse supernova simulations, we find that lower compactness pro-
genitors that explode quasi-spherically due to the short delay to explosion experience smaller neutron
star recoil kicks in the ∼100−200 km s−1
range, while higher compactness progenitors that explode
later and more aspherically leave neutron stars with kicks in the ∼300−1000 km s−1
range. In ad-
dition, we find that these two classes are correlated with the gravitational mass of the neutron star.
This correlation suggests that the survival of binary neutron star systems may in part be due to their
lower kick speeds. We also find a correlation of the kick with both the mass dipole of the ejecta
and the explosion energy. Furthermore, one channel of black hole birth leaves masses of ∼10 M⊙, is
not accompanied by a neutrino-driven explosion, and experiences small kicks. A second is through
a vigorous explosion that leaves behind a black hole with a mass of ∼3.0 M⊙ kicked to high speeds.
We find that the induced spins of nascent neutron stars range from seconds to ∼10 milliseconds and
that a spin/kick correlation for pulsars emerges naturally. We suggest that if an initial spin biases
the explosion direction, a spin/kick correlation is a common byproduct of the neutrino mechanism of
core-collapse supernovae. Finally, the induced spin in explosive black hole formation is likely large and
in the collapsar range. This new 3D model suite provides a greatly expanded perspective and appears
to explain some observed pulsar properties by default.
Keywords: (stars:) supernovae: general – (stars:) neutron – (stars:) pulsar – neutrinos – hydrodynam-
ics
1. INTRODUCTION
Radio pulsars (Manchester et al. 2005; Kaspi & Kramer 2016), magnetars (Kouveliotou et al. 1998; Kaspi & Be-
loborodov 2017), and low-mass and high-mass X-ray binaries (LMXBs and HMXBs) (Shakura & Sunyaev 1973;
Remillard & McClintock 2006) are or contain neutron stars or black holes (MacLeod & Grindlay 2023) created at the
death of a massive star, oftimes in a core-collapse supernova explosion. Excitingly, the mergers of tight binaries of
stellar-mass black holes and neutron stars have recently been captured as gravitational-wave sources (Abbott et al.
2016). Interestingly, a broad spectrum of observations indicates that the formation of neutron stars oftimes leaves
them with significant kick speeds that range up to ∼1500 km s−1
, with an average kick speed of ∼350-400 km s−1
(Faucher-Giguère & Kaspi 2006; Chatterjee et al. 2009) and possible spin-kick correlations (Holland-Ashford et al.
2017; Katsuda et al. 2018; Ng & Romani 2007). However, the bound neutron star population in globular clusters
suggests that some neutron stars are born with kick speeds below ∼50 km s−1
(Lyne & Lorimer 1994; Arzoumanian
et al. 2002), consistent with the suggestion that the kick distribution could be bimodal (Cordes & Chernoff 1998;
Corresponding author: Adam Burrows
aburrows@princeton.edu
arXiv:2311.12109v1
[astro-ph.HE]
20
Nov
2023
2. 2
Arzoumanian et al. 2002; Verbunt et al. 2017). In contradistinction, studies of black holes in X-ray binaries imply
average kick speeds for them of less than ∼50 km s−1
(Fragos et al. 2009; Vigna-Gómez et al. 2023; MacLeod &
Grindlay 2023), but with a few possible exceptions (Mandel 2016; Fragos et al. 2009; Repetto et al. 2017; Atri et al.
2019; Dashwood Brown et al. 2023).
These data and inferences require explanation in the context of compact object birth, i.e. in the context of core-
collapse supernova explosions (CCSNe). The Blaauw mechanism due to unbinding of progenitor binaries as a result
of explosive mass loss (Blaauw 1961; Hills 1970; Hoogerwerf et al. 2001) is quantitatively inadequate, though often
subdominantly operative. Models that invoke asymmetrical radio pulsar winds (Harrison & Tademaru 1975) are not
compelling (Lai et al. 2001). Models that rely on neutrino jets in the context of rapid rotation at birth (Spruit &
Phinney 1998) are not consistent with modern CCSN simulations (Janka 2017; Stockinger et al. 2020; Burrows et al.
2020; Burrows & Vartanyan 2021; Coleman & Burrows 2022). The most comprehensive and well-developed theory for
pulsar and black hole kicks at birth involves recoil due to the generically asymmetrical supernova explosion (Burrows
& Hayes 1996; Scheck et al. 2006; Burrows et al. 2007; Nordhaus et al. 2010, 2012; Wongwathanarat et al. 2013; Janka
2017; Coleman & Burrows 2022) and to the accompanying aspherical neutrino emissions (Fryer & Kusenko 2006;
Nagakura et al. 2019b), the latter generally being subdominant for neutron star birth but important for black hole
birth (Coleman & Burrows 2022).
However, with very few exceptions (Stockinger et al. 2020; Coleman & Burrows 2022), the required sophisticated
and expensive 3D simulations have not been continued to late enough times after bounce to achieve asymptotic kick
speeds. Most such simulations are stopped within one second or less after bounce, far to soon to witness the final kick
speed imparted. Moreover, even the exceptional longer-term 3D studies did not explore the systematics with the broad
range of progenitor masses to determine the correlations between kick speed and progenitor mass and/or initial core
structure, the latter frequently associated with the compactness parameter 1
. They focused on the few models whose
recoil kick had quickly settled to nearly a final state. Hence, a comprehensive theoretical study of the broad spectrum
of systematic behaviors in the context of modern 3D core-collapse supernova theory has not yet been performed. With
this paper, we attempt to remedy this situation by providing and analyzing twenty of our recent long-term state-of-
the-art 3D Fornax(Skinner et al. 2019) simulations for initially non-rotating ZAMS (zero-age main-sequence star)
solar-metallicity progenitors from 9 to 60 M⊙ taken from Sukhbold et al. (2016) and Sukhbold et al. (2018). Many of
these models have been carried in 3D beyond four seconds after bounce and show signs of asymptoting to their final
recoil kick speeds. A few of these models have or will form black holes.
In this paper, we complement our kick study with a study of the associated induced spins (Blondin & Mezzacappa
2007; Rantsiou et al. 2011; Coleman & Burrows 2022). Though a compelling explanation for pulsar and neutron star
spins is spin up from an initially spinning Chandrasekhar core upon collapse, modern supernova simulations leave
proto-neutron star (PNS) cores spinning due to random and stochastic post-explosion accretion of angular momentum
(L), even when the core is initially non-rotating. In fact, the magnitude of such induced spins (Coleman & Burrows
2022) can be comparable to measured pulsar spins (Chevalier & Emmering 1986; Lyne & Lorimer 1994; Manchester
et al. 2005; Faucher-Giguère & Kaspi 2006; Popov & Turolla 2012; Igoshev & Popov 2013; Noutsos et al. 2013).
Moreover, there are hints that radio pulsar spins and kicks might be correlated at birth (Wang et al. 2006, 2007;
Johnston et al. 2005, 2007; Ng & Romani 2007; Noutsos et al. 2013) Finally, angular momentum transport from
the stellar core to the mantle up to the time of core collapse might perhaps be more efficient than hitherto thought
(Cantiello et al. 2014), leaving the Chandrasekhar core slowly rotating just before implosion. Therefore, we continue
here the exploration of the possibility that pulsar spins might be partially or wholly reflective of induced spins during
the supernova. Similarly, black holes created in supernova explosions (Burrows et al. 2023) will have both large kicks
and significant induced spin parameters (a = Lc/GM2
), though black holes created in a non-exploding context should
have birth spins reflective of the initial progenitor spin (though perhaps in a complicated fashion.)
We used the code Fornax (Skinner et al. 2019; Radice et al. 2019; Nagakura et al. 2019a,b; Vartanyan et al. 2019;
Burrows et al. 2019; Burrows et al. 2020; Vartanyan & Burrows 2020; Nagakura et al. 2020; Vartanyan et al. 2022, 2023;
Burrows et al. 2023) to generate the twenty 3D models to late times after bounce used here to study recoil kicks and
induced spins in the context both of supernova explosions and quiescent black hole formation. A more comprehensive
set of studies using these new 3D simulations is in preparation which will address other aspects and outcomes of
1 The compactness parameter is defined to be
M/M⊙
R(M)/1000km
, for which we generally prefer to set M = 1.75M⊙. The O’Connor & Ott (2011)
paper which originated the use of compactness did so in the context of black hole formation and used a value near the maximum neutron
star baryon mass of 2.5 M⊙, which is less appropriate in the supernova context.
3. 3
core-collapse and their dependence upon progenitor. This is the largest set of long-term (many seconds after bounce)
3D state-of-the-art core-collapse simulations ever created and we hope to use it to gain new insights into the core-
collapse supernova phenomenon. To create this set, we employed the CPU machines TACC/Frontera (Stanzione et al.
2020) and ALCF/Theta and the GPU machines ALCF/Polaris and NERSC/Perlmutter. The specific setups and run
parameters are described in Burrows et al. (2023) and Vartanyan et al. (2023). The techniques employed to derive the
kicks and induced spins are described in detail in Coleman & Burrows (2022) and follow the standard approaches in
the literature (Scheck et al. 2006; Wongwathanarat et al. 2013; Stockinger et al. 2020). However, for the calculation
of the neutrino component, unlike in the Coleman & Burrows (2022) paper, we calculate its contribution here at the
PNS radius (defined as the 1011
g cm−3
isosurface), and not at the outer mass surface of the final proto-neutron star
(PNS). The result for the final total vector kick is the same, but there is a different partitioning between the neutrino
and matter components. The momentum transfer between the matter and the radiation in the region between these
two definitions accounts for the shift and the total momentum is conserved under both approaches. We employ the
different method here to comport with the standard practice in the literature (Stockinger et al. 2020).
2. KICKS TO NEUTRON STARS AT BIRTH
Until recently, 3D models experiencing kicks had been calculated to post-bounce times insufficient to actually witness
their final values. Moreover, due to computational limitations, the systematics with progenitor core structure and total
ZAMS mass were obscured, since only one or a few models early during the accumulating recoil could be simulated.
This is akin to viewing the entire progenitor panorama through a straw. The stochasticity of the final values of
any explosion observable inherent in the chaotic turbulence of the CCSN phenomenon also served to compromise
extrapolation and interpretation. However, with our new set of twenty long-term 3D full-physics simulations, we are
now able to extract what we suggest are real trends across the progenitor continuum and find correlations among
observables hitherto only imperfectly glimpsed. Hence, though for all core-collapse supernova observables there are
expected to be a distribution of values, even for the same progenitor, the availability of a raft of such models across the
progenitor continuum mitigates in part against this modest impediment to determining system-wide trends. This is
the philosophy of our multi-model study, enabled by the efficiency of Fornax and the availability of high-performance
computing resources.
Table 1 provides summary numbers of relevance to this study. The top rank displays the data for the exploding
models that leave neutron stars (NS), while the bottom rank displays the corresponding data for the models that
leave black holes (BH) (see §2.1), either quiescently or explosively. Most of the models have either asymptoted to the
final state (in particular the lowest-mass, lowest-compactness progenitors) or nearly so. The left-hand side of Figure 1
depicts the temporal evolution of the absolute value of the vector kick, including both the matter and neutrino recoils
and all momentum flux, pressure, and gravitational forces (Coleman & Burrows 2022). The lowest-mass progenitors
generally flatten/asymptote earliest, while the models with the largest compactness (frequently more massive) take
longer. Such long-duration 3D simulations have not in the past been available.
The right-hand side of Figure 1 depicts the final kicks versus final gravitational mass of the corresponding neutron
stars. This is a plot of observables that has not been available before and speaks to the importance of long-term 3D
simulations to provide testable predictions for modern CCSN theory. We note that the lowest mass progenitors (blue)
are all clustered at the low end of the kick range. This is correlated with the greater degree of sphericity of models
that explode early, before the post-shock turbulence can grow to significant strength and Mach number to manifest
the growth of large bubbles, that when explosion ensues lead it and set an explosion direction. For these initially
non-rotating progenitors, the direction of explosion is random, but once determined a crude axis is set. This is not
the case for the lowest compactness progenitors that explode early and, hence, more spherically.
Figure 2 depicts this dichotomy. Its left-hand side portrays the blast as traced by the 10% iso-56
Ni surface of the
explosion of the 9 M⊙ progenitor, colored by Mach number. Purple is positive (outward) and blue is inward (infall).
The shock wave is the spherical bluish veil around the 56
Ni bubbles. In contrast, the right-hand side of Figure 2
depicts the corresponding plot for the exploding 23 M⊙ model 2
. This model has been carried to ∼6.2 seconds after
bounce and is only slowly asymptoting, while the 9 M⊙ progenitor flattened within 2 seconds (Coleman & Burrows
2022). The blast structure of the 23 M⊙ model is more generic, and this is reflected in the separation of the blue dots
2 We note that the dipole and the monopole decomposition of the shock shape are unstable under roughly similar conditions at roughly the
same times (Burrows 2013; Dolence et al. 2013), rendering a roughly dipolar explosion a common feature if turbulence has been allowed to
grow after the shock initially stalls. This is the case for all but the quickest explosions (generally associated with the lowest compactness).
4. 4
on the right-hand side of Figure 1 from the rest. The latter are spread between ∼300 km s−1
and ∼1000 km s−1
and
the former are found near ∼100−200 km s−1
; the difference reflects the dichotomy illustrated in Figure 2 3
.
The right-hand side of Figure 1 suggests a partial solution to the binary neutron star mass function conundrum;
the gravitational masses measured for them are on average on the low side (Fan et al. 2023) and they seem a distinct
population in mass. Since such binary systems can survive only if the explosions do not unbind them, and kicks
associated with not just one supernova, but two, must be survived. The fact that we predict that the lower-mass
neutron stars are birthed (on average) with lower kick speeds suggests that the lower kicks for this mass range help
select those systems that eventually form binary neutron stars. This correlation emerges naturally, without tweaking,
from the modern theory of turbulence-aided neutrino-driven supernova explosions. It is also the case that even lower-
mass progenitors not in our sample (such as the 8.8 M⊙ progenitor of Nomoto (1984) and accretion-induced collapse
(AIC) systems) would naturally also experience small kicks and these could play a role. Such progenitors are also likely
to explode quickly and experience only very modest kicks (though if rapidly rotating could experience asymmetric
MHD jets that could result in interesting recoils). The lowest progenitor mass range and AIC systems might be
relevant as sources for the neutron stars bound in globular clusters, for which the kick speeds need to be smaller that
the potential well depths (≤50 km s−1
).
The left-hand side of Figure 3 depicts the temporal evolution of the corresponding neutrino contribution to the kick.
This is its absolute value and in the total kick provided in Figure 1 the matter and neutrino terms are vectorially
added; the two are not generally aligned and their individual instantaneous directions vary with time. We see that
the lowest ZAMS mass progenitors (such as the 9 M⊙ model) have some of the highest neutrino kicks (Coleman &
Burrows 2022), but that most other models at higher compactness whose explosions are more delayed have lower
neutrino kick contributions. Moreover, since the matter contributions to the kicks for the more delayed explosions are
generally larger, the neutrino contributions are proportionately less for them and can be as low as ∼3%. They are,
on the other hand, as high as ∼80% for the lowest mass/compactness progenitors. We emphasize, however, that the
chaos of the CCSN phenomenon can result in a range of values for all observables and that this range has not yet been
well determined.
On the right-hand side of Figure 3 we provide a plot of total kick magnitude derived versus the mass dipole of the
ejecta. The latter is a measure of the explosion asymmetry. We see that the two are roughly correlated, as expected
for the general recoil model of kicks, but that there is a bit of scatter. In Figure 4, we provide a similar plot of the kick
magnitude versus the explosion energy. The rough trends of kick with explosion energy and with ejecta mass dipole is
clear and generally expected (Burrows et al. 2007; Janka 2017).
2.1. Black Hole Kicks
Which progenitor massive stars leave stellar-mass black holes at their endpoints is not yet firm. Despite years
of speculation, most of which was uninformed by what at any time was the current (though evolving) state-of-the-
art supernova theory, there remains no consensus among workers in the field concerning the progenitor/black-hole
mapping. The simple idea that above a ZAMS mass cut black holes are the residues of collapse and below that cut
neutron stars are left now seems untenable. We ourselves have found (though not proven) that a 60 M⊙ star leaves a
neutron star (see Table 1). This is consonant with the discovery in the young cluster Westerlund 1 of a neutron star
(Muno et al. 2006) that from the cluster’s turnoff age must be from a progenitor with a ZAMS mass greater than 40
M⊙. This also calls into question a helium core mass cut (perhaps near ∼10 M⊙) (Burrows 1987), above which black
holes form, despite the fact that the stellar-mass black-hole mass function seems to peak near this mass (MacLeod &
Grindlay 2023) and such solar-metallicity stars should often leave stripped-envelope structures (either by mass transfer
or winds).
Moreover, a simplistic compactness cut, above which black holes are birthed at stellar death, is also inconsistent
with the emerging theory of a turbulence-aided neutrino-driven supernova explosion. Neutrino-driven explosions with
energies near ∼1051
ergs require high compactness to achieve. Without rapid initial rotation and an associated MHD-
driven explosion, the low compactness progenitors are not capable of generating explosions in the 1051
ergs (one
3 We emphasize that recoil kicks are merely a manifestation of momentum conservation. Matter is exploded predominantly in one general
direction over a period of time, and the residual neutron star recoils in response. This is like the rocket effect. The effect of the gravitational
accelerations is transient. The gravitational tug of the ejecta is modest and is in the wrong direction to explain the kick. There is a transient
gravitational tug of matter accreting roughly opposite to the mean direction of the ejecta and this is in the general direction into which
the neutron star is eventually kicked. This matter is mostly infall/fallback and most of this matter is accreted at later times onto the
final neutron star. Hence, since these two structures eventually merge, their mutual tug effect is completely cancelled for the final, slightly
fattened neutron star. As a result, the suggestion that a “gravitational tugboat” is responsible for the final kick is mostly an artifact of the
failure to carry a calculation until accelerations cease and the kick asymptotes.
5. 5
Bethe) range. Higher compactness is necessary to provide the higher accretion luminosities and higher “optical”
neutrino depths in the absorbing post-shock mantle and gain region (Bethe & Wilson 1985) to provide the power to
drive the explosion much above the few ×1050
ergs we find for the lowest mass progenitors (8.8 to 9.5 M⊙), which
possess the lowest compactnesses.
Therefore, a simple mass or compactness cut, above which black holes are the endpoints and below which neutron
stars are born doesn’t seem correct. This leaves this issue unresolved. However, we (Wang et al. 2022; Tsang et al.
2022; Burrows et al. 2020; Burrows et al. 2023) have recently found a region of progenitor space between ∼12 and
15 M⊙ where for some subset of initial density profiles in that interval we do not see explosions via the neutrino
mechanism using the collection of solar-metallicity massive stars above 9 M⊙ (Sukhbold et al. 2016, 2018). A fraction
in this gap skirt explosion in the context of our 2D and 3D simulations, and this fraction could be ∼one-third to
∼two-thirds. This outcome could be because 1) the progenitor models we have employed have some flaw or because 2)
our simulations may have some flaw or do not capture some essential physics. Nevertheless, we emphasize that in the
context of our detailed 3D simulations the mass interval for this channel is almost wholly a function of the progenitor
model suite, which is still very much provisional. Which mass range gives birth to black holes quiescently via the route
we identify might shift significantly.
However, perhaps such an interval is indeed a nursery for stellar-mass black hole formation. Two of the models in
the second rank of Table 1, the 12.25 and 14 M⊙ models, are in this interval and do not explode. Even after ∼two to
three seconds after bounce, their stalled shocks continue to sink in radius. Curiously, when the shock is this compact,
a spiral SASI mode (Blondin & Shaw 2007) is excited that modulates the neutrino and gravitational-wave signatures
(Vartanyan et al. 2023) in a diagnostic way. Generally, it is only when the stalled shock sinks below ∼120 km (usually
below ∼100 km) that any form of SASI mode emerges from under neutrino-driven convection and this usually presages
a failed explosion (though see below).
As Table 1 indicates, the kicks to these black holes are quite small. Since the models don’t explode, there would
be no matter recoil and the kick would be due solely to anisotropic neutrino emission. If all the mass that resides in
these models were to be accreted, given the momentum imparted to the cores and the eventual accretion of the the
total mass of ∼11−12 M⊙ remaining after the integrated mass loss up to collapse is factored in (Sukhbold et al. 2016,
2018), kicks of ∼7−8 km s−1
are expected. However, we think it quite likely that further mass loss due to possible
Roche-lobe overflow, common envelope evolution, and/or impulsive mass loss near the time of collapse (Morozova
et al. 2018; Antoni & Quataert 2023) may shave more mass from these progenitors before collapse, leaving ∼8−12 M⊙
left for black holes created through this channel. Interestingly, this mass range roughly coincides with the peak of the
measured range of masses of the relevant X-ray sources (MacLeod & Grindlay 2023).
Note that since these models shouldn’t experience the general-relativistic instability until minutes to hours later
(Vartanyan et al. 2023), and since we have not simulated to those times, our models manifest some stochastic recoil
(see Table 1) due to turbulence around the still accreting PNS. However, we suggest that since the near-terminal
stages of massive star evolution and Type IIp light curves (Morozova et al. 2018) show signs of late-time mass ejection
that may be aspherical, the recoil momentum from such events might find its way into the black hole. The result
could be another component to the speed with which the black hole is born. Whether this component could have a
magnitude of ∼100−200 km s−1
(Mandel 2016; Fragos et al. 2009; Repetto et al. 2017; Atri et al. 2019; Dashwood
Brown et al. 2023) is to be determined. Otherwise, we find that the kicks imparted to such black holes not associated
with explosions are below ∼10 km s−1
, with some likely scatter.
However, as we have recently published (Burrows et al. 2023), there may be another channel of black hole formation
that is accompanied by vigorous explosions. Despite (or because of) the fact that these models have the highest
compactness in the Sukhbold et al. (2016) solar-metallicity collection, the 19.56 and 40 M⊙ progenitors exploded
vigorously with energies of > 2 × 1051
ergs and 1.9×1051
ergs, respectively, as of ∼4 and 21 seconds after bounce.
Curiously, the spiral SASI that emerged for the lower-mass black hole formers that did not encourage explosion did
so for their much-higher compactness counterparts. This is because the high compactness models also experience high
accretion rates that translate into high neutrino luminosities. This combination of high luminosity at a time that the
spiral SASI slightly pushed out the shock and enlarged the gain region was adequate to ignite explosion. As Table 1
and Figure 3 show, this channel of black hole formation not only is explosive with large energies, but has very large
kicks. This is due to the anisotropic neutrino-driven jets and anisotropic accretion during explosion, each of which
contribute to significant recoil kicks (Burrows et al. 2023). Moreover, for these models, even though the neutrino
contribution is still subdominant, it reaches values of hundreds of km s−1
. By the end of these simulations, the recoil
6. 6
momentum achieved is the highest among our set of twenty progenitors. With an estimated final gravitational mass of
∼3.5 M⊙ (the rest is exploded away), the 40 M⊙ progenitor is racing at ∼1000 km s−1
. Such a black hole is unlikely
to remain bound to a companion.
Therefore, we suggest there are at least two channels of black hole formation − one leaving black holes quiescently
in the ∼8−11 M⊙ range with low kick speeds and another leaving black holes explosively in the ∼2.5 − 3.5 M⊙ mass
range with significant proper motions. We note that we have not studied sub-solar-metallicity models, for which the
core compactness structures and wind mass loss are quite different, that we have not simulated models above 60 M⊙,
and that we have not addressed pair-instability models (Woosley & Heger 2021) likely to provide another, though
rarer, black hole formation channel.
3. INDUCED SPINS
Though the rotation profiles of the cores of massive stars at stellar collapse are not known, we know that massive
star surfaces rotate. The loss of angular momentum to winds is guaranteed, but its magnitude is a function of surface
B-fields, which themselves are less well-known. Furthermore, the redistribution of angular momentum in the stellar
interior is no doubt via magnetic torques, but the processes and couplings are not firmly constrained. The fact that red
giant interiors are rotating more slowly (Cantiello et al. 2014) than inferred using a Taylor-Spruit dynamo (Spruit 2002)
suggests a more efficient spin-down process than employed by Heger et al. (2005) in estimating the spin at collapse
of massive-star models. The latter found using a Taylor-Spruit prescription for angular momentum redistribution
that the Chandrasekhar cores might have initial periods at collapse near ∼30−60 seconds, which would translate by
angular momentum conservation into neutron star periods of ∼30−60 milliseconds (Ott et al. 2006), with the lowest
mass massive stars spinning the slowest. Hence, since these periods are not much different from those expected for
radio pulsars (Chevalier & Emmering 1986; Lyne & Lorimer 1994; Manchester et al. 2005; Faucher-Giguère & Kaspi
2006; Popov & Turolla 2012; Igoshev & Popov 2013; Noutsos et al. 2013), it would seem that the issue of the initial
spin period of the cores of massive stars is resolved, at least in broad outline.
However, it is still possible that many of the cores of massive stars destined to undergo collapse may be torqued
down significantly. This thought is motivated not only by the results of Cantiello et al. (2014), but by observation
that white dwarfs are born rotating very slowly (Kawaler 2015; Fuller et al. 2019). Could this be the fate of a good
fraction of the white dwarf cores of massive stars when they die? In order to explore this possibility, one first needs
theoretical insight into what induced spins are possible in the context of core-collapse supernovae. This is what we
provide in this paper.
The left-hand side of Figure 5 renders the evolution of the angular momentum imparted to the PNS cores during
their post-bounce evolution. This spin up is due to the stochastic accretion of plumes of infalling matter into the
PNS, with varying impact parameters. If the explosion is very asymmetrical, as is the case when the kick speeds are
significant, or black hole formation is accompanied by an explosion, the consequently asymmetrical accretion during
explosion (mostly then from one side) can spin the PNS up to interesting periods. For the black holes that form in
an explosion, these spins can reach high values (see Table 1), even though their cores were initially not rotating. This
implies that such objects could be collapsar candidates (Heger & Woosley 2003), despite their lack of initial spin and
their solar-metallicity progenitors.
The right-hand side of Figure 5 portrays the dependence of the final induced spin period of the neutron star upon
ZAMS mass. We see a trend, roughly recapitulated with the kick systematics (see Table 1), of decreasing period
with increasing ZAMS mass, but with a lot of scatter. Such scatter should be expected in the context of the chaotic
turbulence seen in 3D simulations of CCSNe. We emphasize that the lowest ZAMS mass and compactness progenitors
which explode early and approximately spherically have the slowest induced spin rates, while those exploding later
and at higher compactness have greater induced spin rates. In fact, our highest compactness models can leave cold
neutron stars with high angular momenta and spins. However, while we are comfortable with the compactness/kick
and PNS mass/kick correlations we derive, we are much less sanguine that induced spins are the whole story of compact
object birth spins. Importantly, we know that the Crab explosion involved a low-mass progenitor near ∼9−10 M⊙
(Stockinger et al. 2020), but that its birth spin was ∼15 milliseconds (Lyne et al. 2015). This is far from the induced
periods (many seconds) we find for this mass range of progenitors, not only suggesting, but requiring, the story to be
more complicated. Spin-up by binary interaction is also distinctly possible (Fuller & Lu 2022). Therefore, the relative
roles of induced and initial spins in the distribution of observed birth periods for compact objects remains open.
7. 7
Nevertheless, we find an intriguing correlation between induced spin and recoil kicks, demonstrated in Figure 6. The
greater the kick, the greater the induced spin, again with significant scatter. Is there something of importance in this
apparent correlation? Is there rough support for this, however complicated by the overlapping effect of the initial spin,
in the pulsar database?
The induced spins for the non-exploding black hole channel (see Table 1) are quite low, again resulting solely from
from the torques due to the radiated neutrinos. Spin parameters of close to zero are inferred from our simulations and
model extrapolations. However, should there be any significant angular momentum in the accreting stellar envelope
that on long timescales will bulk up the core (something quite likely), these numbers can be radically changed. Hence,
even under the assumption that the initial core spin rate is zero, we can not say with any confidence what the final
spin parameter of black holes born through this channel, might be.
However, the induced spins for the exploding black hole channel can be large. This can follow from the significant
asymmetry in their explosions, itself related to the large recoil kick. A spin parameter as large as ∼0.6 emerges for the
40 M⊙ model (see Table 1), though we have yet to determine the corresponding number for the 19.56 M⊙ model. Their
large compactnesses and related large post-explosion asymmetrical mass accretion rates are direct causative factors.
In addition, accretion continues to power the driving neutrino emissions, which for this black hole formation channel
are quite large. Accretion settles into biased accretion onto one general side and spins up the periphery of the PNS
before black hole formation. After black hole formation, continued accretion parallels continued spin up until after
many seconds the black hole is isolated (for the 40 M⊙ model after ∼50 seconds?). This general black hole formation
scenario is discussed in Burrows et al. (2023).
4. SPIN-KICK CORRELATION
Figure 2 portrays the Mach number for 56
Ni surfaces and the crudely axial explosions when the compactness is not
small and when there is a greater delay to explosion. It also indicates that there is continued accretion roughly in the
perpendicular plane. Hence, when the compactnesses and ZAMS masses are not small, explosion and accretion are
roughly perpendicular. Accretion then spins up the periphery of the PNS and the net spin vector is either roughly
parallel or anti-parallel to the kick (which is along or anti-parallel to the explosion axis). Hence, a spin-kick correlation
naturally emerges from the default theory of neutrino-driven explosions. Figure 7 depicts the dot product of the
final spin and kick unit vectors for our model set, versus ZAMS mass (left) and compactness (right). We see that
there is a deficit in the perpendicular direction and that there is a preference for an (anti-)aligned orientation. This
result provides a natural explanation for the spin-kick correlation for radio pulsars some reseachers have identified
(Holland-Ashford et al. 2017; Katsuda et al. 2018; Ng & Romani 2007).
Moreover, such a correlation may survive even when the Chandrasekhar core is initially rotating, since such rotation
may slightly bias (depending upon its magnitude) the axis and ejecta mass dipole vector of the subsequent neutrino-
driven explosion. If such is the case, then the spin-kick correlation we find here would be universal. The structures seen
in Figure 2 would be qualitatively unaltered. Continued accretion is roughly perpendicular to the explosion direction,
itself roughly (anti-) parallel to the kick direction, resulting in a (anti-)correlation between spin and kick. Note that
we have not invoked B-fields nor MHD jets and that this is an expected outcome in the neutrino-driven explosion
context. However, we emphasize that we have yet to perform the requisite rotating simulations. Nevertheless, the
rough correlation behavior suggested in Figure 7 seems compelling.
5. CONCLUSIONS
With a focus on the recoil kicks imparted to the residues of stellar core collapse in the supernova and black hole
formation contexts, we have analyzed twenty state-of-the-art 3D long-term core-collapse simulations generated using
the code Fornax. In the past, most 3D models were not of sufficient duration to witness the cessation of net
acceleration and the asymptoting of the kicks to their final values. This includes our own previous work (Coleman &
Burrows 2022), as well as that of other workers in the field. However, and for the first time for a large and uniform
collection of 3D supernova models, we have either asymptoted the kicks, or come within 20% of doing so. As a result,
we obtain an integrated and wide-angle perspective of the overall dependence of the kicks and induced spins upon
progenitor mass and their Chandrasekhar-like core structures, the latter indexed approximately by compactness.
We find that lower mass and lower compactness progenitors that explode quasi-spherically due to the short delay to
explosion experience on average smaller kicks in the ∼100−200 km s−1
range, while higher mass and higher compactness
progenitors that explode later and more aspherically give birth to neutron stars with kicks in the ∼300−1000 km s−1
8. 8
range. We also find that these two classes can be correlated with the gravitational mass of the residual neutron star.
The correlation of a lower kick speed with lower neutron star gravitational mass suggests that the survival of binary
neutron star systems, for which their mean mass is lower than average, may in part be due to the lower kick speeds
we see for them. With some scatter, there is a correlation of the kick with both the mass dipole of the ejecta and the
explosion energy. We also find, as did Coleman & Burrows (2022), that the contribution of the recoil due to anisotropic
neutrino emission can be important for the lowest mass/compactness progenitors.
However, unlike Coleman & Burrows (2022), we partition the fractional contribution of the neutrino component
to the overall kick differently, which results in an apparent diminution of its contribution for higher ZAMS mass
and compactness progenitors, for which the matter recoil effect then predominates. The difference with Coleman &
Burrows (2022) is a consequence of our use here of the standard literature radius at which to calculate the neutrino
contribution, and not due to some major differences with the overall results in Coleman & Burrows (2022). Between
the effective radius at which the neutrino component is calculated in Coleman & Burrows (2022) and here, there is
momentum transfer between the matter and neutrino radiation that is properly taken into account in the vector sum
of the two provided in both papers.
We find two channels for black hole birth. The first leaves masses of ∼10 M⊙, is not accompanied by a neutrino-
driven explosion, and experiences small kicks, perhaps below ∼10 km s−1
. The second (Burrows et al. 2023) is through
the vigorous, neutrino-driven explosion of a high-compactness progenitor that leaves behind a black hole with a mass
of perhaps ∼2.5−3.5 M⊙ that is kicked to high speeds, perhaps above ∼1000 km s−1
. This second black-hole formation
channel is novel and unexpected, but if true challenges most notions of what can explode. Both channels challenge
prior notions of the mapping between progenitor and outcome and must still be verified. However, in the context of our
CCSN simulations, the associated mass ranges for black hole formation depend entirely upon the as yet unconverged
progenitor suite model. In particular, the ZAMS mass range for our quiescent black hole formation channel could shift
significantly when binarity, overshoot, shell-merger, mixing processes, and the 12
C(α,γ) rate are properly understood.
Associated with kicks are induced spins that accompany them in the context of the modern theory of turbulence-
aided, neutrino-driven supernova explosions. We find that the induced spins of nascent neutron stars range from
a few seconds at low compactness and low progenitor mass to ∼10 milliseconds at higher compactness and higher
ZAMS mass. However, this can not be the whole story of the birth spins of neutron stars, and the relative roles of
initial and induced spins have yet to be determined. Nevertheless, we find that it is in principle possible to explain
the spin rates of some pulsars with the post bounce asymmetrical accretion of net angular momentum in the context
of asymmetrical supernova explosions for which spherical symmetry is generically broken. Moreover, we find that a
spin/kick correlation for pulsars emerges naturally in the context of modern supernova simulations. If there is an
initial spin to the collapsing core, its vector direction could bias the direction of the explosion. If this is the case, the
spin/kick correlation we see in the induced-spin case would transfer to the general case. However, this speculation has
yet to be verified, but, if true, a spin/kick correlation (in a statistical sense) naturally emerges as a byproduct of the
turbulence-aided neutrino mechanism of core-collapse supernova explosions.
In the non-exploding case of black hole formation, the induced spins are quite low and due to anisotropic neutrino
emission. Any slight neutrino torques would be due to a random stochastic residual effect. Under these circumstances,
an initial spin would be determinative. However, for the exploding context of black hole formation, the induced spin is
likely to be large. For our 40 M⊙ progenitor, we find that the spin parameter could reach ∼0.6 (the maximum is 1.0).
This is in the collapsar range, and suggests that even an initially non-rotating, solar-metallicity, high compactness
progenitor could be a seat of long-soft gamma-ray bursts, with a vigorous explosive precursor. This is a controversial
claim, and one that needs much further scrutiny. However, this is what is suggested by our simulations.
It must be remembered that the chaos in the turbulence generic and fundamental to core collapse phenomena will
result in a spread of outcomes, even for a given progenitor. This translates into distribution functions for the explosion
energies, nucleosynthesis, morphology, kicks, and induced spins that are not delta functions and are currently unknown.
Hence, there is natural scatter in the kicks and induced spins for a given initial model that has yet to be determined,
but that will spread observed values. Some of the scatter seen in this study no doubt originates in this behavior. Such
are the wages of chaos. Nevertheless, though the study of a single 3D model could distort one’s understanding, the
study of a wide range of progenitor structures should provide a more complete picture of the theoretical trends and
correlations that will minimize some of the confusion due to such scatter. In any case, this is the philosophy of this
3D multi-model, long-term exploration of the core-collapse, but much more remains to be done. In particular, we have
employed only one set of initial progenitors and it is clear that such modeling is in flux. Furthermore, though Fornax
9. 9
is a sophisticated tool, it incorporates no approach to neutrino oscillations, uses a moment-closure approach to the
radiative transfer, and incorporates approximate, not precise, general relativity. Nevertheless, the greatly expanded
panorama the new capabilities and this new numerical database provide is qualitatively more comprehensive and
predictive, due to its breadth and temporal extent, than has heretofore been possible and appears to explain many
observed pulsar properties by default.
ACKNOWLEDGMENTS
We thank Chris White for previous insights, collaboration, and conversations. We acknowledge support from the U. S.
Department of Energy Office of Science and the Office of Advanced Scientific Computing Research via the Scientific
Discovery through Advanced Computing (SciDAC4) program and Grant DE-SC0018297 (subaward 00009650) and
support from the U. S. National Science Foundation (NSF) under Grants AST-1714267 and PHY-1804048 (the latter
via the Max-Planck/Princeton Center (MPPC) for Plasma Physics). Some of the models were simulated on the
Frontera cluster (under awards AST20020 and AST21003), and this research is part of the Frontera computing project
at the Texas Advanced Computing Center (Stanzione et al. 2020). Frontera is made possible by NSF award OAC-
1818253. Additionally, a generous award of computer time was provided by the INCITE program, enabling this research
to use resources of the Argonne Leadership Computing Facility, a DOE Office of Science User Facility supported
under Contract DE-AC02-06CH11357. Finally, the authors acknowledge computational resources provided by the
high-performance computer center at Princeton University, which is jointly supported by the Princeton Institute for
Computational Science and Engineering (PICSciE) and the Princeton University Office of Information Technology, and
our continuing allocation at the National Energy Research Scientific Computing Center (NERSC), which is supported
by the Office of Science of the U. S. Department of Energy under contract DE-AC03-76SF00098.
DATA AVAILABILITY
The numerical data underlying this article will be shared upon reasonable request to the corresponding author.
REFERENCES
Abbott, B. P., Abbott, R., Abbott, T. D., et al. 2016, Phys.
Rev. Lett., 116, 061102,
doi: 10.1103/PhysRevLett.116.061102
Antoni, A., & Quataert, E. 2023, MNRAS, 525, 1229,
doi: 10.1093/mnras/stad2328
Arzoumanian, Z., Chernoff, D. F., & Cordes, J. M. 2002,
The Astrophysical Journal, 568, 289–301,
doi: 10.1086/338805
Atri, P., Miller-Jones, J. C. A., Bahramian, A., et al. 2019,
MNRAS, 489, 3116, doi: 10.1093/mnras/stz2335
Bethe, H. A., & Wilson, J. R. 1985, ApJ, 295, 14,
doi: 10.1086/163343
Blaauw, A. 1961, BAN, 15, 265
Blondin, J. M., & Mezzacappa, A. 2007, Nature, 445,
58–60, doi: 10.1038/nature05428
Blondin, J. M., & Shaw, S. 2007, ApJ, 656, 366,
doi: 10.1086/510614
Breu, C., & Rezzolla, L. 2016, MNRAS, 459, 646,
doi: 10.1093/mnras/stw575
Burrows, A. 1987, Physics Today, 40, 28,
doi: 10.1063/1.881086
—. 2013, Reviews of Modern Physics, 85, 245,
doi: 10.1103/RevModPhys.85.245
Burrows, A., & Hayes, J. 1996, Physical Review Letters, 76,
352–355, doi: 10.1103/PhysRevLett.76.352
Burrows, A., Livne, E., Dessart, L., Ott, C. D., & Murphy,
J. 2007, The Astrophysical Journal, 655, 416–433,
doi: 10.1086/509773
Burrows, A., Radice, D., & Vartanyan, D. 2019, MNRAS,
485, 3153, doi: 10.1093/mnras/stz543
Burrows, A., Radice, D., Vartanyan, D., et al. 2020,
Monthly Notices of the Royal Astronomical Society, 491,
2715–2735, doi: 10.1093/mnras/stz3223
Burrows, A., & Vartanyan, D. 2021, Nature, 589, 29,
doi: 10.1038/s41586-020-03059-w
Burrows, A., Vartanyan, D., & Wang, T. 2023, arXiv
e-prints, arXiv:2308.05798,
doi: 10.48550/arXiv.2308.05798
Cantiello, M., Mankovich, C., Bildsten, L.,
Christensen-Dalsgaard, J., & Paxton, B. 2014, ApJ, 788,
93, doi: 10.1088/0004-637X/788/1/93
Chatterjee, S., Brisken, W. F., Vlemmings, W. H. T., et al.
2009, The Astrophysical Journal, 698, 250–265,
doi: 10.1088/0004-637X/698/1/250
Chevalier, R. A., & Emmering, R. T. 1986, ApJ, 304, 140,
doi: 10.1086/164150
10. 10
Coleman, M. S. B., & Burrows, A. 2022, MNRAS, 517,
3938, doi: 10.1093/mnras/stac2573
Cordes, J. M., & Chernoff, D. F. 1998, The Astrophysical
Journal, 505, 315–338, doi: 10.1086/306138
Dashwood Brown, C., Gandhi, P., & Zhao, Y. 2023,
MNRAS, doi: 10.1093/mnrasl/slad151
Dolence, J. C., Burrows, A., Murphy, J. W., & Nordhaus,
J. 2013, The Astrophysical Journal, 765, 110,
doi: 10.1088/0004-637X/765/2/110
Fan, Y.-Z., Han, M.-Z., Jiang, J.-L., Shao, D.-S., & Tang,
S.-P. 2023, arXiv e-prints, arXiv:2309.12644,
doi: 10.48550/arXiv.2309.12644
Faucher-Giguère, C.-A., & Kaspi, V. M. 2006, ApJ, 643,
332, doi: 10.1086/501516
Fragos, T., Willems, B., Kalogera, V., et al. 2009, ApJ, 697,
1057, doi: 10.1088/0004-637X/697/2/1057
Fryer, C. L., & Kusenko, A. 2006, ApJS, 163, 335,
doi: 10.1086/500933
Fuller, J., & Lu, W. 2022, MNRAS, 511, 3951,
doi: 10.1093/mnras/stac317
Fuller, J., Piro, A. L., & Jermyn, A. S. 2019, MNRAS, 485,
3661, doi: 10.1093/mnras/stz514
Harrison, E. R., & Tademaru, E. 1975, The Astrophysical
Journal, 201, 447–461, doi: 10.1086/153907
Heger, A., & Woosley, S. E. 2003, in American Institute of
Physics Conference Series, Vol. 662, Gamma-Ray Burst
and Afterglow Astronomy 2001: A Workshop Celebrating
the First Year of the HETE Mission, ed. G. R. Ricker &
R. K. Vanderspek, 214–216, doi: 10.1063/1.1579341
Heger, A., Woosley, S. E., & Spruit, H. C. 2005, ApJ, 626,
350, doi: 10.1086/429868
Hills, J. G. 1970, Nature, 226, 730, doi: 10.1038/226730a0
Holland-Ashford, T., Lopez, L. A., Auchettl, K., Temim,
T., & Ramirez-Ruiz, E. 2017, The Astrophysical Journal,
844, 84, doi: 10.3847/1538-4357/aa7a5c
Hoogerwerf, R., de Bruijne, J. H. J., & de Zeeuw, P. T.
2001, A&A, 365, 49, doi: 10.1051/0004-6361:20000014
Igoshev, A. P., & Popov, S. B. 2013, Monthly Notices of the
Royal Astronomical Society, 432, 967–972,
doi: 10.1093/mnras/stt519
Janka, H.-T. 2017, The Astrophysical Journal, 837, 84,
doi: 10.3847/1538-4357/aa618e
Johnston, S., Hobbs, G., Vigeland, S., et al. 2005, MNRAS,
364, 1397, doi: 10.1111/j.1365-2966.2005.09669.x
Johnston, S., Kramer, M., Karastergiou, A., et al. 2007,
MNRAS, 381, 1625,
doi: 10.1111/j.1365-2966.2007.12352.x
Kaspi, V. M., & Beloborodov, A. M. 2017, ARA&A, 55,
261, doi: 10.1146/annurev-astro-081915-023329
Kaspi, V. M., & Kramer, M. 2016, arXiv e-prints,
arXiv:1602.07738. https://arxiv.org/abs/1602.07738
Katsuda, S., Morii, M., Janka, H.-T., et al. 2018, ApJ, 856,
18, doi: 10.3847/1538-4357/aab092
Kawaler, S. D. 2015, in Astronomical Society of the Pacific
Conference Series, Vol. 493, 19th European Workshop on
White Dwarfs, ed. P. Dufour, P. Bergeron, &
G. Fontaine, 65, doi: 10.48550/arXiv.1410.6934
Kouveliotou, C., Dieters, S., Strohmayer, T., et al. 1998,
Nature, 393, 235, doi: 10.1038/30410
Lai, D., Chernoff, D. F., & Cordes, J. M. 2001, The
Astrophysical Journal, 549, 1111–1118,
doi: 10.1086/319455
Lyne, A. G., Jordan, C. A., Graham-Smith, F., et al. 2015,
MNRAS, 446, 857, doi: 10.1093/mnras/stu2118
Lyne, A. G., & Lorimer, D. R. 1994, Nature, 369, 127–129,
doi: 10.1038/369127a0
MacLeod, M., & Grindlay, J. 2023, arXiv e-prints,
arXiv:2304.09368, doi: 10.48550/arXiv.2304.09368
Manchester, R. N., Hobbs, G. B., Teoh, A., & Hobbs, M.
2005, AJ, 129, 1993, doi: 10.1086/428488
Mandel, I. 2016, MNRAS, 456, 578,
doi: 10.1093/mnras/stv2733
Morozova, V., Piro, A. L., & Valenti, S. 2018, ApJ, 858, 15,
doi: 10.3847/1538-4357/aab9a6
Muno, M. P., Clark, J. S., Crowther, P. A., et al. 2006,
ApJL, 636, L41, doi: 10.1086/499776
Nagakura, H., Burrows, A., Radice, D., & Vartanyan, D.
2019a, Monthly Notices of the Royal Astronomical
Society, 490, 4622–4637, doi: 10.1093/mnras/stz2730
—. 2020, Monthly Notices of the Royal Astronomical
Society, 492, 5764–5779, doi: 10.1093/mnras/staa261
Nagakura, H., Sumiyoshi, K., & Yamada, S. 2019b, The
Astrophysical Journal Letters, 880, L28,
doi: 10.3847/2041-8213/ab30ca
Ng, C.-Y., & Romani, R. W. 2007, The Astrophysical
Journal, 660, 1357–1374, doi: 10.1086/513597
Nomoto, K. 1984, ApJ, 277, 791, doi: 10.1086/161749
Nordhaus, J., Brandt, T. D., Burrows, A., & Almgren, A.
2012, Monthly Notices of the Royal Astronomical Society,
423, 1805–1812, doi: 10.1111/j.1365-2966.2012.21002.x
Nordhaus, J., Brandt, T. D., Burrows, A., Livne, E., & Ott,
C. D. 2010, Physical Review D, 82, 103016,
doi: 10.1103/PhysRevD.82.103016
Noutsos, A., Schnitzeler, D. H. F. M., Keane, E. F.,
Kramer, M., & Johnston, S. 2013, Monthly Notices of the
Royal Astronomical Society, 430, 2281–2301,
doi: 10.1093/mnras/stt047
O’Connor, E., & Ott, C. D. 2011, ApJ, 730, 70,
doi: 10.1088/0004-637X/730/2/70
11. 11
Ott, C. D., Burrows, A., Thompson, T. A., Livne, E., &
Walder, R. 2006, The Astrophysical Journal Supplement
Series, 164, 130–155, doi: 10.1086/500832
Popov, S. B., & Turolla, R. 2012, Astrophysics and Space
Science, 341, 457–464, doi: 10.1007/s10509-012-1100-z
Radice, D., Morozova, V., Burrows, A., Vartanyan, D., &
Nagakura, H. 2019, The Astrophysical Journal, 876, L9,
doi: 10.3847/2041-8213/ab191a
Rantsiou, E., Burrows, A., Nordhaus, J., & Almgren, A.
2011, The Astrophysical Journal, 732, 57,
doi: 10.1088/0004-637X/732/1/57
Remillard, R. A., & McClintock, J. E. 2006, ARA&A, 44,
49, doi: 10.1146/annurev.astro.44.051905.092532
Repetto, S., Igoshev, A. P., & Nelemans, G. 2017, MNRAS,
467, 298, doi: 10.1093/mnras/stx027
Scheck, L., Kifonidis, K., Janka, H.-T., & Müller, E. 2006,
Astronomy and Astrophysics, 457, 963–986, doi: bb
Shakura, N. I., & Sunyaev, R. A. 1973, A&A, 24, 337
Skinner, M. A., Dolence, J. C., Burrows, A., Radice, D., &
Vartanyan, D. 2019, The Astrophysical Journal
Supplement Series, 241, 7, doi: 10.3847/1538-4365/ab007f
Spruit, H., & Phinney, E. S. 1998, Nature, 393, 139–141,
doi: 10.1038/30168
Spruit, H. C. 2002, A&A, 381, 923,
doi: 10.1051/0004-6361:20011465
Stanzione, D., West, J., Evans, R. T., et al. 2020, in
Practice and Experience in Advanced Research
Computing, PEARC ’20 (New York, NY, USA:
Association for Computing Machinery), 106–111,
doi: 10.1145/3311790.3396656
Stockinger, G., Janka, H. T., Kresse, D., et al. 2020,
MNRAS, 496, 2039, doi: 10.1093/mnras/staa1691
Sukhbold, T., Ertl, T., Woosley, S. E., Brown, J. M., &
Janka, H. T. 2016, ApJ, 821, 38,
doi: 10.3847/0004-637X/821/1/38
Sukhbold, T., Woosley, S. E., & Heger, A. 2018, ApJ, 860,
93, doi: 10.3847/1538-4357/aac2da
Tsang, B. T. H., Vartanyan, D., & Burrows, A. 2022,
ApJL, 937, L15, doi: 10.3847/2041-8213/ac8f4b
Vartanyan, D., & Burrows, A. 2020, ApJ, 901, 108,
doi: 10.3847/1538-4357/abafac
Vartanyan, D., Burrows, A., & Radice, D. 2019, Monthly
Notices of the Royal Astronomical Society, 489,
2227–2246, doi: 10.1093/mnras/stz2307
Vartanyan, D., Burrows, A., Wang, T., Coleman, M. S. B.,
& White, C. J. 2023, PhRvD, 107, 103015,
doi: 10.1103/PhysRevD.107.103015
Vartanyan, D., Coleman, M. S. B., & Burrows, A. 2022,
MNRAS, 510, 4689, doi: 10.1093/mnras/stab3702
Verbunt, F., Igoshev, A., & Cator, E. 2017, A&A, 608, A57,
doi: 10.1051/0004-6361/201731518
Vigna-Gómez, A., Willcox, R., Tamborra, I., et al. 2023,
arXiv e-prints, arXiv:2310.01509,
doi: 10.48550/arXiv.2310.01509
Wang, C., Lai, D., & Han, J. L. 2006, The Astrophysical
Journal, 639, 1007–1017, doi: 10.1086/499397
—. 2007, The Astrophysical Journal, 656, 399–407,
doi: 10.1086/510352
Wang, T., Vartanyan, D., Burrows, A., & Coleman, M.
S. B. 2022, MNRAS, 517, 543,
doi: 10.1093/mnras/stac2691
Wongwathanarat, A., Janka, H.-T., & Müller, E. 2013,
Astronomy and Astrophysics, 552, A126,
doi: 10.1051/0004-6361/201220636
Woosley, S. E., & Heger, A. 2021, ApJL, 912, L31,
doi: 10.3847/2041-8213/abf2c4
12. 12
MZAMS ξ1.75 tmax Type Mbaryonic Mgrav pkick/1040
vtotal
kick vν
kick L/1046
Pcold
[M⊙] [s] [M⊙] [M⊙] [g cm s−1
] [km s−1
] [km s−1
] [g cm2
s−1
] [ms]
9(a) 6.7 × 10−5
1.775 NS 1.347 1.237 3.235 120.7 87.4 1.046 749.1
9(b) 6.7 × 10−5
2.139 NS 1.348 1.238 2.106 78.6 59.1 0.190 4132
9.25 2.5 × 10−3
3.532 NS 1.378 1.263 3.842 140.1 93.2 0.344 2346
9.5 8.5 × 10−3
2.375 NS 1.397 1.278 5.796 208.6 77.5 1.636 501.5
11 0.12 4.492 NS 1.497 1.361 20.83 699.4 90.5 23.28 38.54
15.01 0.29 4.384 NS 1.638 1.474 5.668 173.9 10.6 6.995 144.2
16 0.35 4.184 NS 1.678 1.505 15.62 468.0 63.5 20.23 51.45
17 0.74 3.458 NS 2.039 1.731 25.07 618.2 66.3 100.0 13.59
18 0.37 5.631 NS 1.680 1.507 22.64 677.4 81.6 10.55 98.85
18.5 0.80 3.954 NS 2.146 1.859 31.60 740.2 55.7 10.06 145.3
19 0.48 4.075 NS 1.803 1.603 18.89 526.7 30.6 68.05 16.85
20 0.79 4.620 NS 2.139 1.854 21.04 494.5 6.46 15.62 93.14
23 0.74 6.228 NS 1.959 1.722 10.94 280.8 75.9 9.294 138.2
24 0.77 3.919 NS 2.028 1.773 36.79 912.1 34.9 37.58 35.88
25 0.80 4.639 NS 2.100 1.826 23.13 553.8 56.3 22.42 63.19
60 0.44 5.369 NS 1.786 1.590 29.37 826.5 47.3 120.4 9.406
MZAMS ξ1.75 tmax Type Mbaryonic Mfinal pkick/1040
vtotal
kick vν
kick L/1046
a
[M⊙] [s] [M⊙] [M⊙] [g cm s−1
] [km s−1
] [km s−1
] [g cm2
s−1
]
12.25 0.34 2.090 BH (F) 1.815 ∼11.1 1.441 39.9 (10.7) 39.9 (6.90) 3.621 0.002 (0.0004)
14 0.48 2.824 BH (F) 1.990 ∼12.1 1.684 42.5 (9.59) 42.5 (7.9) 4.638 0.003 (0.0004)
19.56 0.85 3.890 BH (S) 2.278 ? 82.76 1826 (?) 28.1 (?) 12.83 0.006 (?)
40 0.87 1.76 (21) BH (S) 2.434 ∼3.5 72.85 1504(1034) 79.5 (83.0) 84.32 0.039 (0.6)
Table 1. Results for the simulations presented in this work. MZAMS is the initial ZAMS mass of the progenitor model.
tmax is the maximum post-bounce time reached by the simulation. For the black hole formers, the times are the time of
black hole formation, and the second time (if shown) is the latest time after black hole formation we have carried that model
hydrodynamically. The types of central objects are summarized. NS means neutron star, BH (F) means black hole formed with
a failed explosion, and BH (S) means black hole formed accompanied by a successful CCSN explosion. Mbaryonic is the baryonic
mass of the central object at tmax, while Mgrav is the gravitational mass of a cold, catalyzed NS. Mfinal is the estimated final black
hole mass. The final masses of the non-exploding black hole formers are the total masses in the progenitor models at collapse,
assuming all matter will eventually be accreted, while the final masses of the exploding black hole formers are derived from our
hydro-only blast wave simulations after black hole formation. pkick gives the linear momentum of the object at tmax. v
(total)
kick and
v
(ν)
kick are the total kick speeds and the kick speeds induced by neutrinos only, respectively. Both are measured at tmax. Numbers
in brackets show the estimated final values (kick speed, spin parameter) of the black holes. Note that the 40-M⊙ model has
been simulated to 21 seconds after bounce, at which point the spin parameter has reached ∼0.35, and that we estimate its final
gravitational mass and spin parameter (a) will be ∼3.5 M⊙ 0.6, respectively, achieved after a further ∼25 seconds of evolution.
We have yet to determine the corresponding numbers for the 19.56 M⊙ model. These numbers still need to be checked. Lcentral
is the angular momentum of the central object at tmax, and Pcold is the inferred final spin period of the cold final neutron star,
assuming P = 2πLcentral
INS
. The neutron star moment of inertia is estimated using INS = (0.237 + 0.674ξNS + 4.48ξ4
NS)MR2
NS,
where ξNS = GM
RNSc2 is the compactness parameter of the neutron star itself (Breu & Rezzolla 2016). We assume here that the
final neutron star radius is RNS = 12km. For black holes, the relativistic spin parameter a = Lc
GM2 is shown and the number in
brackets is our guess for its of final value.
13. 13
Figure 1. Left: Total kick velocity as a function of time in each simulation. Solid lines are models that form neutron stars,
while dashed lines are black hole formers. Right: Kick versus cold NS gravitational mass. Black hole formers are not included
here.
Figure 2. An isosurface (10%) of the 56
Ni abundance in the explosion of a 9 M⊙ (left) and 23 M⊙ (right) progenitor model at
∼1.95 and ∼6.2 seconds, respectively, after bounce, painted by Mach number. Red/purple is positive and white/blue is negative,
indicating infall. This figure is a representative depiction of a generic feature of core-collapse explosions by the turbulence-aided
neutrino-driven mechanism, mainly that there is often simultaneous explosion in one general direction and accretion in a very
roughly perpendicular direction when the explosion time is delayed by a few hundred milliseconds (as for the 23 M⊙ model) and
a more spherical explosion when it is launched early (within ∼50−100 milliseocnds), as for an initially non-rotating (or slowly
rotating), low-compactness progenitor, such as this 9 M⊙ model. This fact has a bearing on the morphology of the debris, line
profiles in supernova ejecta, and spin-kick correlations. Since most explosions are delayed and manifest some bubble-driven
dipolarity, the explosion direction for most progenitors (anti-)correlates with the kick direction and the accretion in a roughly
perpendicular direction correlates with the (induced)spin up. See text for discussions on this finding.
14. 14
Figure 3. Left: Neutrino kick velocity as a function of time. Solid lines are models that form neutron stars, while dashed
lines are black hole formers. Right: Mass dipole versus final total kick speed. Note that those models that seem to deviate
from linearity (e.g., the 23 M⊙ model) are also those models which have yet to asymptote, suggesting that a roughly linear
relationship is even more robust than this figure implies.
Figure 4. Magnitude of the final kick speed versus explosion energy. The range of energies reflects the fact that some of these
model energies have not yet asymptoted; we provide an informed range when they don’t and the simulation of these models is
still proceeding.
15. 15
Figure 5. Left: Total angular momentum as a function of time for each simulation. Solid lines are models that form neutron
stars, while dashed lines are black hole formers. Right: Estimated neutron star angular velocity versus progenitor ZAMS mass
calculated assuming Ltot
INS
. Only neutron star formers are shown here. The neutron star moment of inertia is estimated using
(0.237 + 0.674ξ + 4.48ξ4
)MR2
NS, where ξ = GM
RNSc2 is the compactness parameter of the neutron star itself (Breu & Rezzolla
2016). We assume here that the final neutron star radius is RNS = 12 km.
Figure 6. Relation between kick speeds and induced spins of neutron stars birthed in initially non-rotating progenitor stars.
16. 16
Figure 7. Cosine of the angle between the kick and induced spin directions versus ZAMS mass (left) and compactness (right).
Circles are models that form neutron stars, while triangles are black hole formers.