TY - JOUR
T1 - xGASS: total cold gas scaling relations and molecular-to-atomic gas ratios of galaxies in the local Universe
AU - Catinella, Barbara
AU - Saintonge, Amélie
AU - Janowiecki, Steven
AU - Cortese, Luca
AU - Davé, Romeel
AU - Lemonias, Jenna J.
AU - Cooper, Andrew P.
AU - Schiminovich, David
AU - Hummels, Cameron B.
AU - Fabello, Silvia
AU - Geréb, Katinka
AU - Kilborn, Virginia
AU - Wang, Jing
PY - 2018/1/12
Y1 - 2018/1/12
N2 - 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⋆ =
109-1011.5 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, Rmol, 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 Rmol,
especially at fixed specific star formation rate. On average,
Rmol 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 Rmol 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.
AB - 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⋆ =
109-1011.5 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, Rmol, 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 Rmol,
especially at fixed specific star formation rate. On average,
Rmol 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 Rmol 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.
KW - galaxies: evolution
KW - galaxies: fundamental parameters
KW - galaxies: ISM
KW - radio lines: galaxies
U2 - 10.1093/mnras/sty089
DO - 10.1093/mnras/sty089
M3 - Article
VL - 476
SP - 875
EP - 895
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 1
ER -