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Galaxy And Mass Assembly (GAMA): improved cosmic growth measurements using multiple tracers of large-scale structure

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posted on 2023-06-08, 16:52 authored by C Blake, I K Baldry, J Bland-Hawthorn, L Christodoulou, M Colless, C Conselice, S P Driver, A M Hopkins, J Liske, Jonathan LovedayJonathan Loveday, P Norberg, J A Peacock, G B Poole, A S G Robotham
We present the ?rst application of a ‘multiple-tracer’ redshift-space distortion (RSD) analysis to an observational galaxy sample, using data from the Galaxy and Mass Assembly (GAMA) survey. Our data set is an r < 19.8 magnitude-limited sample of 178 579 galaxies covering the redshift interval z < 0.5 and area 180 deg2. We obtain improvements of 10–20 per cent in measurements of the gravitational growth rate compared to a single-tracer analysis, deriving from the correlated sample variance imprinted in the distributions of the overlapping galaxy populations. We present new expressions for the covariances between the auto-power and cross-power spectra of galaxy samples that are valid for a general survey selection function and weighting scheme. We ?nd no evidence for a systematic dependence of the measured growth rate on the galaxy tracer used, justifying the RSD modelling assumptions, and validate our results using mock catalogues from N-body simulations. For multiple tracers selected by galaxy colour, we measure normalized growth rates in two independent redshift bins fs8(z = 0.18) = 0.36 ± 0.09 and fs8(z = 0.38) = 0.44 ± 0.06, in agreement with standard GR gravity and other galaxy surveys at similar redshifts

History

Publication status

  • Published

File Version

  • Published version

Journal

Monthly Notices of the Royal Astronomical Society

ISSN

0035-8711

Publisher

Oxford University Press

Issue

4

Volume

436

Page range

3089-3105

Department affiliated with

  • Physics and Astronomy Publications

Notes

Advance Access publication 2013 October 22

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2014-03-12

First Open Access (FOA) Date

2014-03-12

First Compliant Deposit (FCD) Date

2014-03-12

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