6.2 Pests of Sesame_Identification_Binomics_Dr.UPR
Astana spherex
1. Constraints on initial
conditions from the large
scale structure formation
Yong-Seon Song
(Korea Astronomy and Space Science Institute)
New Prospective of Cosmology, APCTP
February 17th 2017
2. New phase to probe initial conditions
Although the spectral index clearly indicates that it departs ns=1, we
need confirming evidence for inflationary initial condition. But there is
no proof of primordial gravitation wave.
Demands for alternative evidences
3. Future target of astronomy community
Most observed wavebands of galaxies have been targeted at optical
bands. The remaining targets will be NIR or FIR regions in which
star forming and astro-biological informations are available.
Optic bands
Star Formation ICE
Demand for Space Telescope
4. Possible collaboration with cosmology
1. Full sky observation is possible at space: horizon size clustering
2. Redshift indicator: quick and rush spectroscopy searches
It can be useful for initial condition constraints
5. Building 3-D catalogue for initial condition
• From our full-sky 97 bands, we extract the spectra of
known sources using the full-sky catalogs from
PanSTARRS/DES and WISE.
➡ Blending and confusion are easily controlled.
• We compare this spectra to a template library (robust for
low redshift sources):
➡ For each galaxy, we obtain a redshift but also other
properties (stellar mass, dust content…).
• We simulated this process extensively using the COSMOS
data-set using the same methodology as the one used for
Euclid/WFIRST (Capak et al.).
• A spectra is obtained for any type of galaxy and not only
ELGs:
➡ Ideal for multi-tracer studies (McDonald & Seljak 09).
• The power of low-resolution spectroscopy has been
demonstrated with PRIMUS (Cool++14), COSMOS (Ilbert+
+09), NMBS (van Dokkum++09).
• The 1.6 μm bump is a well known universal photometric
redshift indicator (e.g., Simpson & Eisenhardt 99)
6. All sky galaxy density
• Full source extraction and redshit measurement pipeline (Capak & Masters).
• Detect 1.4 billions sources:
➡ 301M of which with 10% z accuracy, 120M with 3% and 9.8M 0.3%.
• Spectra of all types of galaxies, i.e., not only emission line galaxies:
➡ Ideally suited for multi-tracer studies.
• The high σ(z) sample drives the power-spectrum fNL constraints while the lower σ(z) sample
drive the bispectrum and other cosmological parameter constraints.
σ(z)/(1+z)
7. Primordial Non-Gaussianity affects galaxy clustering
• The effect of primordial non-Gaussianity on galaxy clustering is most important on large scales
➡ Full sky survey, low spectral resolution sample.
• E.g., SDSS QSOs : −49 < fNL
loc < 31 (95% C.L., Leistedt & Peiris 13)
8. Probing the effective non-Gaussianity
Definition of scale dependent bias
Observable non-Gaussianity current bound: fNL < 5.8
10. All sky galaxy density
• Full source extraction and redshit measurement pipeline (Capak & Masters).
• Detect 1.4 billions sources:
➡ 301M of which with 10% z accuracy, 120M with 3% and 9.8M 0.3%.
• Spectra of all types of galaxies, i.e., not only emission line galaxies:
➡ Ideally suited for multi-tracer studies.
• The high σ(z) sample drives the power-spectrum fNL constraints while the lower σ(z) sample
drive the bispectrum and other cosmological parameter constraints.
σ(z)/(1+z)
Power Spectrum
Bispectrum
11. Current status of projects
JPL and KASI submitted the SPHEREx project
to NASA SMEX program (2016)
1. The submitted proposal was unsuccessful
2. There are demands for surveys with bigger telescopes, which exceeds
the limit of SMEX program
3. NASA recommends the program to be upgraded to be submitted for
middle class space telescope call
JPL will lead middle class space telescope call, and CosKASI
stays in collaborating in data analysis (2017 on going)
12. Probing a large effective volume
Veff = Vsurvey
s
Pgal
Pgal + 1
ngal
13. Why Studying primordial non-Gaussianity?
Testing Inflation with Large Scale Structure: Connecting Hopes with Reality
(conveners: O.Dore, D. Green, Alvarez et al., arXiv:1412.4671)
14. New phase to probe the initial condition
We plan to launch the full sky survey to access the horizon mode
structure formation to probe fNL using both power and bi spectra.
Thermal shields
Spacecraft boresight
Instrument boresight
Instrument boresight is
canted so NCP/SCP can
be viewed even when
spacecraft tilts for Sun-
avoidance
15. Instrument structure
OBA
S/C Top Deck
RING
WE=FW+SW
CE
BAFFLE
FPA
Radiators
“Warm” Harness (WH)
COVER
COLDRADIATOR
FPA = Focal Plane Assembly
OBA = Optical Bench Assembly
WE = Warm Electronics
CE = Cold Electronics (SIDECARs)
C&DH TELECOM
Solar Shield
Assembly
Thermal
Structural
Assembly
Electronics
System
Optical System
16. Parameter for spacecraft SPHEREx
We define the spacecraft SPHEREx parameters for measuring
galaxy spectroscopy to determine redshift.
Parameter Required Value Capability Value
Telescope aperture 20 cm
Focal ratio 3
Band 1 0.75 – 1.25 um; λ/Δλ = 40; H2RG-2.5 um
Band 2 1.25 – 2.10 um; λ/Δλ = 40; H2RG-2.5 um
Band 3 2.10 – 3.50 um; λ/Δλ = 40; H2RG-5 um
Band 4 2.60 – 5.00 um; λ/Δλ = 150; H2RG-5 um
Total FOV 3.5 deg x 7 deg
Pixel size 6 x 6
Optics temperature 80 K
5um array temperature 50 K
Total efficiency 30 % 50 %
Pointing jitter (1σ, 200 s) 3 1.5
Large (70º) slew time 150 s 90 s
Small (10′) slew time 20 s 10 s
Read noise CDS 18/15 e- 10.5 e-
17. Spectroscopy pipeline
7ºx3.5°
6pixels
B4: 2.6 - 5.0 µm T
R = 150
In Transmission
B2: 1.25 - 2.1 µm
R = 40
In Reflection
B1: 0.75 - 1.25 µm
R = 40
In Reflection
λ !λ !
2048 x 2048 2048 x 2048
Full coverage requires 20 steps
across each detector (100 for Band 4)
Teledyne H2RG arrays
- H1RGs flown on HST (1.7um),
OCO (2.5um), WISE (5um) (TRL 9)
- H2RGs and SIDECAR for JWST (TRL 6)
- H2RGs wide use in ground-based astronomy
LVFs in space applications
- HST as order sorters
- ISO as CVFs
- OSIRIS-Rex for spectral imaging
- Ralph/New Horizons for spectral imaging
FOV:
B3: 2.1 - 3.5 µm T
R = 40
In Transmission
18. Bispectrum Configuration
Configuration in redshift space
k1 k2
k3
𝛍1
𝛍2
B(k1,k2,k3,𝛍1,𝛍2)
We choose this specific configuration because it is easy to include
FoG effect and to handle AP projection.
We include all possible configuration as each parameter is
extractable at specific configuration.
19. Full covariance approach
F 𝝰𝝱 = 𝝨k 𝝨k1k2k3 (𝞉S/𝞉p 𝝰) C-1 (𝞉S/𝞉p 𝝱)
S = P(k,𝛍)
(
C-1 = M -MCPBCBB-1
-CBB-1CBB-1M CBB-1+CBB-1CBpMCPBCBB-1
Fisher matrix is given by
where the vector field S is given by
The full covariance matrix is given by,
This full covariance calculation is performed for DESI forecast.
B(k1,k2,k3,𝛍1,𝛍2))
( )
22. Challenges to be faced
We have never applied 1.6 micro bump as redshift indicators
before. We will need the pathfinder
1. KASI launches the 40cm class space telescope NISS in 2017
2. It provides the full SED covered by the future telescope with lower
sensitivity
In order to constraints on non-Gaussianity of bispectrum, we need
to understand the bispectrum higher order polynomials
1. The squeezed higher order connected terms are known to be non-
negligible in power spectrum case
2. The lowest order contributions of the squeezed higher order terms are
not next order in bispectrum
23. The Simulated Field
The FoV of NISS is correspondent to 4 sq. degrees, so we cut the
same size of SDSS field.
24. Theoretical SED model using SDSS data
We use MAGPHYS to fit SED over NISS range of 0.9𝛍m to 3.5𝛍m
SDSS SDSS
We will have approximately 10,000 galaxies
25. Selection of targeted fields
We pay attention to GAMA DR2 galaxies with 21 band photometry
1. Using full band GAMA galaxies, we run MAGPHYS and estimate SED
2. We select galaxy samples which have spectroscopy follow up
3. We locate bump peak assuming narrow bandwidth & low magnitude
4. We select a group galaxy having consistent bump peak and true z
5. We vary threshold selection z resolution limit from 10-3 to 10-4
27. Simulating NISS data
There will be 28 data points on NISS simulated SED
1. Generating simulated data from 0.9𝛍m to 3.5 𝛍m for selected galaxy
2. We apply NISS magnitude limit over 28 bins
3. We run SED code to determine z after fully marginalising others
4. We compare it with true z which is given by GAMA spectroscopy
28. Challenges to be faced
We have never applied 1.6 micro bump as redshift indicators
before. We will need the pathfinder
1. KASI launches the 40cm class space telescope NISS in 2017
2. It provides the full SED covered by the future telescope with lower
sensitivity
In order to constraints on non-Gaussianity of bispectrum, we need
to understand the bispectrum higher order polynomials
1. The squeezed higher order connected terms are known to be non-
negligible in power spectrum case
2. The lowest order contributions of the squeezed higher order terms are
not next order in bispectrum
29. Bispectrum seen at redshift space
First order (equivalent to Kaiser term)
Second order
FoG term
𝝙 = 𝛅+𝝻2ϴ
30. Mapping of clustering from real to redshift spaces
Ps(k,𝝻) = ∫d3x eikx ⟨𝛅𝛅⟩
Ps(k,μ) = ∫d3x eikx ⟨ejv (𝛅+𝝻2ϴ)(𝛅+𝝻2ϴ)⟩
• Higher order polynomials are generated by density and velocity
cross-correlation which generate the infinite tower of correlation
pairs. We take the perturbative approach to cut off higher orders.
= ∫d3x eikx exp{⟨ejv⟩c} [⟨ejv(𝛅+𝝻2ϴ)(𝛅+𝝻2ϴ)⟩c+⟨ejv(𝛅+𝝻2ϴ)⟩c⟨ejv(𝛅+𝝻2ϴ)⟩c]
Ps(k,μ) = [Pgg(k) + 2𝝻2PgΘ(k) + 𝝻4P 𝛉𝛉(k)+ A(k,𝝻) + B(k,𝝻) + T(k,𝝻) + F(k,𝝻)]
exp[-(k𝝻σp)2]
• The FoG effect consists of the one-point contribution and the
correlated velocity pair contribution. The latter is perturbatively
expanded as F term, and the former is parameterised using σp.
33. Direct measurement of higher order polynomials
A(k,𝝻)
B(k,𝝻)
T(k,𝝻)
F(k,𝝻)
Yi, YSS 2016
34. The residual FoG
We subtract out the perturbative higher order polynomials, and the
remaining’s can be considered to be FoG effect. If our formulation is
correct, those all residuals should be consistent in terms of scale,
and fitted to be Gaussian with constant 𝜎p.
exp[-(k𝝻σp)2]
37. The effect from the squeezed trispectrum
The reconstructed linear spectrum of density and velocity spectra
With the squeezed trispectrum Without the squeezed trispectrum
38. Bispectrum seen at redshift space
First order (equivalent to Kaiser term)
Second order
FoG term
𝝙 = 𝛅+𝝻2ϴ
39. Conclusion
• We measure coherent motion of the universe with BOSS catalogue
using RSD perturbative theory, which provides us with trustable
measurements.
• The full perturbative approaches allow us to prove the exotic
cosmic acceleration model such as modified gravity of f(R) gravity.
• We probe the non-trivial neutrino mass about 0.2eV, and the
measured Hubble constant gets to be even smaller about 65.
• The future experiment opens new precision cosmology era, and
we are ready for the challenge. Our new RSD theoretical model is
promising to probe coherent motion in a percentage precision.
• The combination of power and bi spectra is essential to probe the
coherent motion tightly. We make lots of efforts for it.
