2019/11/30 by Carlos Hernandez-Monteagudo, Jonas Chaves-Montero, Raul E. Angulo · 1 citation
Physics and Astronomy · #astro-ph.CO
paper · pdf · doi:10.1093/mnrasl/slaa172
6 pages, 3 figures, matches accepted version in MNRAS letters, companion paper of Chaves-Montero et al., arXiv:1911.10690
arxiv created 2021/03/23 · arxiv updated 2021/04/07
We propose the use of angular fluctuations in the galaxy redshift field as a new way to extract cosmological information in the Universe. This new probe δz (n) consists on the statistics of sky maps built by projecting redshifts under a Gaussian window of width σz centred upon a redshift z\rm obs, and weighted by the galaxy density field. We compute the angular power spectrum of the δz (n) field in both numerical simulations and in linear perturbation theory. From these we find that the δz (n) field: \it (i) is sensitive to the underlying density and peculiar velocity fields; \it (ii) is highly correlated, at the \gtrsim 60 % level, to the line-of-sight projected peculiar velocity field; \it (iii) for narrow windows (σz < 0.03), it is almost completely uncorrelated to the projected galaxy angular density field under the same redshift window; and \it (iv) it is largely unaffected by multiplicative and additive systematic errors on the observed number of galaxies that are redshift-independent over ∼σz. We conclude that δz (n) is a simple and robust tomographic measure of the cosmic density and velocity fields, complementary to angular clustering, that will contribute to more complete exploitations of current and upcoming galaxy redshift surveys.