Semi-empirical constraints on the HI mass function of star-forming galaxies and $Ω_{\rm HI}$ at $z\sim 0.37$ from interferometric surveys

Francesco Sinigaglia; Alessandro Bianchetti; Giulia Rodighiero; Lucio Mayer; Miroslava Dessauges-Zavadsky; Ed Elson; Mattia Vaccari; Matt J. Jarvis

doi:10.1051/0004-6361/202555928

paper

Semi-empirical constraints on the HI mass function of star-forming galaxies and $Ω_{HI}$ at $z \sim 0.37$ from interferometric surveys

arXiv:2506.11280 · doi:10.1051/0004-6361/202555928

Abstract

The HI mass function is a crucial tool to understand the evolution of the HI content in galaxies over cosmic times. We aim to derive semi-empirical constraints at $z \sim 0.37$ by combining literature results on the $M_{⋆}$ function from optical surveys with recent findings on the $M_{HI} - M_{⋆}$ scaling relation derived via spectral stacking analysis applied to 21-cm line interferometric data from the MIGHTEE and CHILES surveys, conducted with the MeerKAT and VLA radio telescopes, respectively. We draw synthetic $M_{⋆}$ samples directly from the publicly-available results underlying the analysis of the COSMOS2020 galaxy photometric sample. Afterwards, we convert $M_{⋆}$ into $M_{HI}$ using analytical fitting functions to the data points from HI stacking. We then fit a Schechter function to the median HIMF from all the samples via MCMC. We finally derive the posterior distribution for $Ω_{HI}$ by integrating the models for the HIMF built from the posteriors samples of the Schechter parameters. We find a deviation of the HIMF at $z \sim 0.37$ from the results at $z \sim 0$ from the ALFALFA survey and at $z \sim 1$ from uGMRT data. Our results for $Ω_{HI}$ are in broad agreement with other literature results, and follow the overall trend on $Ω_{HI}$ as a function of redshift. The derived value $Ω_{HI} = (7.0 2_{- 0.52}^{+ 0.59}) \times 1 0^{- 4}$ at $z \sim 0.37$ from the combined analysis deviates at $\sim 2.9 σ$ from the ALFALFA result at $z \sim 0$ . Our findings about the HIMF and $Ω_{HI}$ differ from previous literature results at $z \sim 0$ and $z \sim 1$ , although we are unable to confirm at this stage whether these differences are due to cosmic evolution consistent with a smooth transition of the HI content of galaxies over the last 8 Gyr or due to selection biases and systematics.

arXiv comment19 pages, 14 figures, 5 tables. Accepted for publication in A&A. Current version matching the accepted manuscript

Semi-empirical constraints on the HI mass function of star-forming galaxies and ΩHI​ at z∼0.37 from interferometric surveys

Abstract

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Semi-empirical constraints on the HI mass function of star-forming galaxies and $Ω_{HI}$ at $z \sim 0.37$ from interferometric surveys