- Title
- 2MTF-VI. Measuring the velocity power spectrum
- Creator
- Howlett, Cullan; Staveley-Smith, Lister; Elahi, Pascal J.; Hong, Tao; Jarrett, Tom H.; Jones, D. Heath; Koribalski, Bärbel S.; Macri, Lucas M.; Masters, Karen L.; Springob, Christopher M.
- Relation
- Funding BodyARCGrant NumberCE1101020 http://purl.org/au-research/grants/arc/CE1101020
- Relation
- Monthly Notices of the Royal Astronomical Society Vol. 471, Issue 3, p. 3135-3151
- Publisher Link
- http://dx.doi.org/10.1093/mnras/stx1521
- Publisher
- Oxford University Press
- Resource Type
- journal article
- Date
- 2017
- Description
- We present measurements of the velocity power spectrum and constraints on the growth rate of structure fσ₈, at redshift zero, using the peculiar motions of 2062 galaxies in the completed 2MASS Tully–Fisher survey (2MTF). To accomplish this we introduce a model for fitting the velocity power spectrum including the effects of non-linear redshift space distortions (RSD), allowing us to recover unbiased fits down to scales k = 0.2 h Mpc−1 without the need to smooth or grid the data. Our fitting methods are validated using a set of simulated 2MTF surveys. Using these simulations we also identify that the Gaussian distributed estimator for peculiar velocities of Watkins & Feldman is suitable for measuring the velocity power spectrum, but sub-optimal for the 2MTF data compared to using magnitude fluctuations δm, and that, whilst our fits are robust to a change in fiducial cosmology, future peculiar velocity surveys with more constraining power may have to marginalize over this. We obtain scale-dependent constraints on the growth rate of structure in two bins, finding fσ₈ = [0.55+0.16−0.13,0.40+0.16−0.17] in the ranges k = [0.007–0.055, 0.55–0.150] h Mpc−1. We also find consistent results using four bins. Assuming scale-independence we find a value fσ₈ = 0.51+0.09−0.08, a ∼16 per cent measurement of the growth rate. Performing a consistency check of general relativity (GR) and combining our results with cosmic microwave background data only we find γ = 0.45+0.10−0.11, a remarkable constraint considering the small number of galaxies. All of our results are completely independent of the effects of galaxy bias, and fully consistent with the predictions of GR (scale-independent fσ₈ and γ ≈ 0.55).
- Subject
- cosmological parameters; large-scale structure of Universe; cosmology
- Identifier
- http://hdl.handle.net/1959.13/1396244
- Identifier
- uon:34022
- Identifier
- ISSN:0035-8711
- Language
- eng
- Full Text
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