2015/09/30 by Sebastian Seehars, Aseem Paranjape, Amadeus Witzemann +3 · 18 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Context (archaeology) #Cosmology #Dark Matter and Cosmic Phenomena #Dark matter #Estimator #Field (mathematics) #Galaxies: Formation, Evolution, Phenomena #Halo #Intensity (physics) #Intensity mapping #Redshift #astro-ph.CO
paper · pdf · doi:10.1088/1475-7516/2016/03/001
published in Journal of Cosmology and Astroparticle Physics 2016(03), 001 (Institute of Physics) · 35 pages, 19 Figures. Accepted for publication in JCAP
arxiv created 2016/03/01 · openalex publication_date 2016/03/01 · arxiv updated 2016/03/02 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
Intensity mapping of neutral hydrogen (HI) is a promising observational probe of cosmology and large-scale structure. We present wide field simulations of HI intensity maps based on N-body simulations of a 2.6 Gpc / h box with 2048 3 particles (particle mass 1.6 × 10 11 M ⊙ / h ). Using a conditional mass function to populate the simulated dark matter density field with halos below the mass resolution of the simulation (10 8 M ⊙ / h < M halo < 10 13 M ⊙ / h ), we assign HI to those halos according to a phenomenological halo to HI mass relation. The simulations span a redshift range of 0.35 ≲ z ≲ 0.9 in redshift bins of width Δ z ≈ 0.05 and cover a quarter of the sky at an angular resolution of about 7′. We use the simulated intensity maps to study the impact of non-linear effects and redshift space distortions on the angular clustering of HI. Focusing on the autocorrelations of the maps, we apply and compare several estimators for the angular power spectrum and its covariance. We verify that these estimators agree with analytic predictions on large scales and study the validity of approximations based on Gaussian random fields, particularly in the context of the covariance. We discuss how our results and the simulated maps can be useful for planning and interpreting future HI intensity mapping surveys.