The population of galaxies that contribute to the H  i mass function

Journal Article · Sat Apr 04 00:00:00 EDT 2020 · Monthly Notices of the Royal Astronomical Society

DOI:https://doi.org/10.1093/mnras/staa864· OSTI ID:1615867

Dutta, Saili ^[1]; Khandai, Nishikanta ^[1]; Dey, Biprateep ^[2]

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1. School of Physical Sciences, National Institute of Science Education and Research, HBNI, Jatni 752050, India
2. School of Physical Sciences, National Institute of Science Education and Research, HBNI, Jatni 752050, India, Pittsburgh Particle Physics, Astrophysics and Cosmology Center (PITT PACC) and Department of Physics and Astronomy, University of Pittsburgh, 3941 O’Hara Street, Pittsburgh, PA 15260, USA

ABSTRACT

We look at the contribution of different galaxy populations to the atomic hydrogen (H i) mass function (HIMF) and the H i density parameter, ΩH i, in the local Universe. Our analysis is based on a sample of 7857 H i selected galaxies selected from a volume common to the Sloan Digital Sky Survey (SDSS) and Arecibo Fast Legacy ALFA (40 per cent catalogue – α.40) surveys. We define different populations of galaxies in the colour (u − r)–magnitude (Mr) plane and compute the HIMF for each of them. Additionally we compute the HIMF for dark galaxies; these are undetected in SDSS and represent $$\sim 2{{\ \rm per\ cent}}$$ of the total sample. We find that the luminous red population dominates the total HIMF for $$\log _{10}(M_{\rm{H\,{\small I}}}h^2_{70}/M_{\odot }) \ge 10.4$$. The full red population – luminous and faint – represents about $$\sim 17{{\ \rm per\ cent}}$$ of the ΩH i budget, while that of the dark population is $$\sim 3{{\ \rm per\ cent}}$$. The HIMF about the knee, $$\log _{10}(M_{\rm{H\,{\small I}}}h^2_{70}/M_{\odot }) \in [8,10.4]$$, is dominated by the faint and luminous blue populations, the latter dominating at larger masses in this interval. Their total contribution to ΩH i is $$\sim 55\!-\!70{{\ \rm per\ cent}}$$, the variation depending on the definition of population. The dominant populations at the low-mass end, $$\log _{10}(M_{\rm{H\,{\small I}}}h^2_{70}/M_{\odot }) \le 8.0$$ are the faint blue and faint bluer populations, the latter’s dominance being sensitive to its definition. The full blue (blue–bluer luminous and faint) population represents $$\sim 80{{\ \rm per\ cent}}$$ of ΩH i. A bimodal HIMF suggested by our results is however not seen since the amplitude of the HIMF of the luminous red population is small compared to that of the luminous blue population.

• Sponsoring Organization: USDOE
• OSTI ID: 1615867
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 2 Vol. 494; ISSN 0035-8711
• Publisher: Oxford University Press
• Country of Publication: United Kingdom
• Language: English