Swinburne
Browse

Cosmological forecasts for combined and next-generation peculiar velocity surveys

Download (1.32 MB)
journal contribution
posted on 2024-07-09, 22:58 authored by Cullan Howlett, Lister Staveley-Smith, Chris BlakeChris Blake
Peculiar velocity surveys present a very promising route to measuring the growth rate of large-scale structure and its scale dependence. However, individual peculiar velocity surveys suffer from large statistical errors due to the intrinsic scatter in the relations used to infer a galaxy's true distance. In this context, we use a Fisher matrix formalism to investigate the statistical benefits of combining multiple peculiar velocity surveys. We find that for all cases we consider that there is a marked improvement on constraints on the linear growth rate fσ8. For example, the constraining power of only a few peculiar velocity measurements is such that the addition of the 2MASS Tully–Fisher survey (containing only ∼2000 galaxies) to the full redshift and peculiar velocity samples of the 6-degree Field Galaxy Survey (containing ∼110 000 redshifts and ∼9000 velocities) can improve growth rate constraints by ∼20 per cent. Furthermore, the combination of the future TAIPAN and WALLABY+WNSHS surveys has the potential to reach a ∼3 per cent error on fσ8, which will place tight limits on possible extensions to General Relativity. We then turn to look at potential systematics in growth rate measurements that can arise due to incorrect calibration of the peculiar velocity zero-point and from scale-dependent spatial and velocity bias. For next-generation surveys, we find that neglecting velocity bias in particular has the potential to bias constraints on the growth rate by over 5σ, but that an offset in the zero-point has negligible impact on the velocity power spectrum.

Funding

ARC | CE110001020

History

Available versions

PDF (Published version)

ISSN

1365-2966

Journal title

Monthly Notices of the Royal Astronomical Society

Volume

464

Issue

3

Pagination

2517-2544

Publisher

Oxford University Press (OUP)

Copyright statement

This article has been accepted for publication in the Monthly Notices of the Royal Astronomical Society ©: 2017 the authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

Language

eng

Usage metrics

    Publications

    Categories

    No categories selected

    Keywords

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC