An accurate low-redshift measurement of the cosmic neutral hydrogen density

Wenkai Hu*, Laura Hoppmann, Lister Staveley-Smith, Katinka Geréb, Tom Oosterloo, Raffaella Morganti, Barbara Catinella, Luca Cortese, Claudia del P. Lagos, Martin Meyer

*Bijbehorende auteur voor dit werk

OnderzoeksoutputAcademicpeer review

11 Citaten (Scopus)
52 Downloads (Pure)


Using a spectral stacking technique, we measure the neutral hydrogen (H I) properties of a sample of galaxies at z < 0.11 across 35 pointings of the Westerbork Synthesis Radio Telescope. The radio data contain 1895 galaxies with redshifts and positions known from the Sloan Digital Sky Survey. We carefully quantified the effects of sample bias, aperture used to extract spectra, sidelobes and weighting technique and use our data to provide a new estimate for the cosmic H I mass density. We find a cosmic H I mass density of Ω _{H I} = (4.02 ± 0.26)× 10^{-4} h_{70}^{-1} at <z> = 0.066, consistent with measurements from blind H I surveys and other H I stacking experiments at low redshifts. The combination of the small interferometer beam size and the large survey volume makes our result highly robust against systematic effects due to confusion at small scales and cosmic variance at large scales. Splitting into three sub-samples with <z> = 0.038, 0.067, and 0.093 shows no significant evolution of the H I gas content at low redshift.
Originele taal-2English
Pagina's (van-tot)1619-1632
Aantal pagina's14
TijdschriftMonthly Notices of the Royal Astronomical Society
Nummer van het tijdschrift2
StatusPublished - 1-okt-2019

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