xGASS: total cold gas scaling relations and molecular-to-atomic gas ratios of galaxies in the local Universe

By B. Catinella, A. Saintonge, S. Janowiecki, L. Cortese, R. Dav'e, J. Lemonias, A. Cooper, David Schiminovich, Cameron Hummels, S. Fabello and 3 more. 2018

253 citations recorded by the source corpus.

We present the extended GALEX Arecibo SDSS Survey (xGASS), a gas fraction-limited census of the atomic hydrogen (H I) gas content of 1179 galaxies selected only by stellar mass (M⋆ = 10^9–10^(11.5) M_⊙) and redshift (0.01 < z < 0.05). This includes new Arecibo observations of 208 galaxies, for which we release catalogues and H I spectra. In addition to extending the GASS H I scaling relations by one decade in stellar mass, we quantify total (atomic+molecular) cold gas fractions and molecular-to-atomic gas mass ratios, R_(mol), for the subset of 477 galaxies observed with the IRAM 30 m telescope. We find that atomic gas fractions keep increasing with decreasing stellar mass, with no sign of a plateau down to log M⋆/M_⊙ = 9. Total gas reservoirs remain H I-dominated across our full stellar mass range, hence total gas fraction scaling relations closely resemble atomic ones, but with a scatter that strongly correlates with R_(mol), especially at fixed specific star formation rate. On average, R_(mol) weakly increases with stellar mass and stellar surface density μ⋆, but individual values vary by almost two orders of magnitude at fixed M⋆ or μ⋆. We show that, for galaxies on the star-forming sequence, variations of R_(mol) are mostly driven by changes of the H I reservoirs, with a clear dependence on μ⋆. Establishing if galaxy mass or structure plays the most important role in regulating the cold gas content of galaxies requires an accurate separation of bulge and disc components for the study of gas scaling relations.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/4f6bd9619cfa032b241f60273e3e22d7cfbf0266

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In Astronomy and Astrophysics

Citations in the corpus

The Arecibo Legacy Fast ALFA Survey: The ALFALFA Extragalactic H i Source Catalog (2018, background): “Star formation is linked more closely to the molecular H2 gas (e.g. Kennicutt & Evans 2012; Saintonge et al. 2016; Catinella et al. 2018).”