J/A+A/646/A71 CFHTLenS galaxy bias and redshift distribution (Simon+, 2021)
CFHTLenS: Galaxy bias as function of scale, stellar mass, and colour.
Conflicts with predictions by semi-analytic models.
Simon P., Hilbert S.
<Astron. Astrophys. 646, A71 (2021)>
=2021A&A...646A..71S 2021A&A...646A..71S (SIMBAD/NED BibCode)
ADC_Keywords: Models ; Gravitational lensing ; Galaxies ; Redshifts
Keywords: gravitational lensing: weak - cosmology: observations -
large-scale structure of the Universe - galaxies: evolution
Abstract:
Galaxy models predict a tight relation between the clustering of
galaxies and dark matter on cosmological scales, but predictions
differ notably in the details. We used this opportunity and tested two
semi-analytic models by the Munich and Durham groups with data from
the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS). For the
test we measured the scale-dependent galaxy bias factor b(k) and
correlation factor r(k) from linear to non-linear scales of k≃10h/Mpc
at two redshifts z{bar}=0.35, 0.51 for galaxies with stellar mass
between 5x109 and 3x1011h70-2M{sun|. Our improved
gravitational lensing technique accounts for the intrinsic alignment
of sources and the magnification of lens galaxies for better
constraints for the galaxy-matter correlation r(k). Galaxy bias in
CFHTLenS increases with k and stellar mass; it is colour-dependent,
revealing the individual footprints of galaxy types. Despite a
reasonable model agreement for the relative change with both scale and
galaxy properties, there is a clear conflict for b(k) with no model
preference: the model galaxies are too weakly clustered. This may flag
a model problem at z≳0.3 for all stellar masses. As in the models,
however, there is a high correlation r(k) between matter and galaxy
density on all scales, and galaxy bias is typically consistent with a
deterministic bias on linear scales. Only our blue and low-mass
galaxies of about 7x109h70-2M☉ at z{bar}=0.51 show,
contrary to the models, a weak tendency towards a stochastic bias on
linear scales where rls=0.75±0.14(stat.)±0.06(sys.). This result
is of interest for cosmological probes, such as EG, that rely on a
deterministic galaxy bias. We provide Monte Carlo realisations of
posterior constraints for b(k) and r(k) in CFHTLenS for every galaxy
sample in this paper at the CDS.
Description:
The archive contains estimates of the redshift distributions and
galaxy biasing functions b(k),r(k) for eight galaxy samples SM1, SM2,
..., SM6, RED, BLUE in two photometric redshift bins low-z (∼0.35)
and high-z (∼0.51). The galaxies are selected from the
Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS) Version 1.1.
Please see the accompanying paper for details on the survey data and
the selection criteria (Table 2).
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galaxybias{SM1,SM2,SM3,SM4,SM5,SM6,red,blue}_{low,highz}.dat:
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Monte-Carlo realisations of the posterior distribution of b(k) (third
column) and r(k) (fourth column) as function of the comoving wave
number k (second column). The first column is an integer index between
0 and 999 for the 1000 realisations in every file. The biasing
functions are an average for the entire galaxy sample and the range in
redshift it covers.
The measurements are normalised to a fiducial cosmology (flat LCDM)
which is given in the header of the files. For the amplitude
normalisation, the cosmological density parameter Omega matter (Om) is
most important, while the amplitude of matter fluctuations in the
linear power spectrum, sigma8, is of subordinate relevance (for the
ratio statistics).
The posterior distribution accounts only for statistical errors in the
measurement but not for the systematic errors in the bias
normalisation (Appendix E in paper).
If a random realisation is needed from the file, read the block
{k,b(k),r(k)} for a random index. All realisations have equal
statistical weights.
To propagate the statistical error in your study, repeat your analysis
with a set of random realisations of {k,b(k),r(k)} and evaluate the
scatter in your analysis results.
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redshiftdistribution{SM1,SM2,SM3,SM4,SM5,SM6,red,blue}{low,highz}.dat
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Estimates of the redshift distribution of all galaxy samples, based on
the average, deconvolved BPZ posterior distribution of all galaxies in
the sample (Appendix 2.3 in the paper). The ASCII data file contains
the redshift (first column) and the normalised p(z) (second column).
The data are interpolation points (this is not a histogram); the
lensing analysis uses splines to interpolate between the points.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 80 32 List of files
galaxy/* . 16 Individual galaxy bias files
redshifts/* . 16 Individual redshifts files
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See also:
J/A+A/584/A53 : Code for trispectrum of halo model (Kuntz, 2015)
J/A+A/627/A137 : Cosmology from galaxy lensing and clustering (Jullo+, 2019)
J/MNRAS/452/1171 : Extended X-ray sources in CFHTLenS footprint (Wilcox+, 2015)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Sample Sample
6- 10 A5 --- zbin Photometric redshift bins
(low-z (∼0.35) or high-z (∼0.51)
12- 32 A21 --- Type galaxy bias or redshift distribution
34- 80 A47 --- FileName Name of the file
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Byte-by-byte Description of file (#): galaxy/*
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Bytes Format Units Label Explanations
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1- 3 I3 --- Index [0/999] Integer index
5- 13 F9.6 Mpc-1 ck Comoving k (h/Mpc)
15- 24 E10.5 --- b(K) Posterior distribution of b(K)
26- 35 E10.5 --- r(k) Posterior distribution of r(k)
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Byte-by-byte Description of file (#): redshifts/*
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Bytes Format Units Label Explanations
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1- 10 F10.8 --- z Redshfit
12- 22 E11.9 --- p(z) Normalised p(z)
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Acknowledgements:
Patrick Simon, psimon(at)astro.uni-bonn.de
(End) Patricia Vannier [CDS] 24-Nov-2020