Post on 31-Jul-2020
Study the large-scale structure of theuniverse using galaxy clusters
Bùi Văn TuấnAdvisors: Cyrille Rosset
Michel CrézéDirector: Volker Beckmann
Astroparticle and Cosmology LaboratoryUniversité Paris Diderot
November 10, 2016
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 1 / 16
Outline
1 Scientific context
2 Planck and Euclid missions
3 Estimators of two-point correlation function
4 Simulation of random cluster catalog
5 Current results
6 Conclusion
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 2 / 16
Scientific context
Standard model of cosmology
The large-scale structure
Galaxies, cluster of galaxies, super-clusters and filaments are the largeststructures in the universe.
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 3 / 16
Planck and Euclid missions
Planck mission
Credit: ESA.
Planck is a space mission byESA. (2009 - 2013)
Mission: All-sky CMB surveyusing millimeter wavelengths;Primordial universe (inflation)and dark universe.
Euclid mission
Credit: ESA.
Launch date: 2020.
Mission: galaxy surveys (1.5billions galaxies) for studyingthe dark universe using visibleand near infra-red wavelengths.
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 4 / 16
Estimators of two-point correlation function
Data: Planck SZ cluster catalog
Sunyaev-Zel’dovich effect
Credit: Roman’s these
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 5 / 16
Estimators of two-point correlation function
Data: Planck SZ cluster catalog
Planck Sunyaev-Zel’dovich cluster catalog (1271 clusters) and thePlanck mask map (white area)
Planck SZ cluster catalog
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 5 / 16
Estimators of two-point correlation function
Estimators of two-point correlation function
Measure the excess probability respect to the uniform distribution offinding a galaxy in a sphere area S(θ) at an angular separation θ fromanother galaxy.
Peebles & Hauser (1974):
1 + w1(θ) =DD
RR(1)
Davis & Peebles (1983):
1 + w2(θ) =DD
DR(2)
Landy and Szalay (1993):
wLS(θ) =DD − 2DR + RR
RR(3)
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 6 / 16
Simulation of random cluster catalog
Random galaxy cluster catalogs
- Apply the Planck mask to random uniform clusters.- Each random cluster has angular size θs that corresponds to a noise mapσy500 (32 noise maps of θs from 0.94 to 35.32 arcmin)- Keep clusters have generated y > 4 ∗ σy500.
Generated θs and y500
0 5 10 15 20 25 30 35θs
0.00
0.01
0.02
0.03
0.04
0.05
y500
Planck's ts and y500Generated ts and y500
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 7 / 16
Simulation of random cluster catalog
Random galaxy cluster catalogs
Random uniform cluster catalog
Random uniform catalog
Random cluster applied Planck mask and selection function
Random uniform with Planck maskapplied and selection function
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 7 / 16
Current results
Angular distance of pairs statistics
0 20 40 60 80 100 120 140 160 180θ [degrees]
0.018
0.019
0.020
0.021
0.022
0.023
0.024
0.025Planck
Random uniform
Planck and random uniform with mask applied and selection function
Fake data and Random uniform both with mask applied and selection function
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 8 / 16
Current results
Estimators of Planck catalog and random catalogs
Correlation function of Planck catalog and random catalogs withPlanck mask applied and selection function.
0 20 40 60 80 100 120 140 160 180Angular distance [degrees]
0.10
0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30
Est
imato
r tw
o-p
oin
t co
rrela
tion f
unct
ion
Estitmators of Planck and random uniform catalogs applied maskand selection function
wDD/RR
wDD/DR
wLS
σwDD/RR
σwDD/RR
σwLS
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 9 / 16
Current results
Comparing 3 estimators
Fake cluster catalog and random cluster catalogs, both with the Planckmask applied and selection function.
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 10 / 16
Current results
Comparing 3 estimators
Planck cluster catalog and random catalogs with the Planck mask appliedand selection function
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 11 / 16
Current results
Expect for detection of Baryon acoustic oscillations
– Acoustic wave propagating in the early universe due to thecounteracting forces of radiation pressure and gravity.
– The standard ruler for length scale in cosmology.
– Study the dark energy by constraining cosmological parameters.
(SDSS) - Eisenstein et al., 2005 (SDSS) - G. C. Carvalho et al., 2015
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 12 / 16
Current results
Expect for detection of Baryon acoustic oscillations
– Acoustic wave propagating in the early universe due to thecounteracting forces of radiation pressure and gravity.
– The standard ruler for length scale in cosmology.
– Study the dark energy by constraining cosmological parameters.
(SDSS) - Eisenstein et al., 2005
0.0 0.2 0.4 0.6 0.8 1.00
20
40
60
80
100
120
140Redshift distribution of 926 Planck MMF3 clusters
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 12 / 16
Current results
Ongoing work: Two-point correlation at smaller scale
High correlation around 10 degrees -> Expect to find the BAO signal
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 13 / 16
Conclusion
High correlation of clusters at small angular scale.
The distribution of Planck cluster catalog produce significant signalfrom the departure of the uniform distribution.
The DD/DR estimator has the smallest dispersion, then following bythe estimator DR, and the Landy-Szalay estimator respectively.
Expect for the detection of BAO signal at angular scale around 10degrees.
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 14 / 16
Conclusion
Future work
Estimating the angular correlation function with Euclid requires manysteps (as work was needed to produce the Planck cluster catalog) :
Calibrate and clean images
Find galaxies in images and measure their photometry
Measure their distances (or redshift) using spectroscopic andphotometric redshift methods.
Identify clusters
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 15 / 16
Conclusion
Thank you for your attention!
BUI VAN TUAN (APC) Study the large-scale structure of the universe using galaxy clustersNovember 10, 2016 16 / 16