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

5 Pith papers cite this work. Polarity classification is still indexing.

5 Pith papers citing it
abstract

We present the extended GALEX Arecibo SDSS Survey (xGASS), a gas fraction-limited census of the atomic (HI) gas content of 1179 galaxies selected only by stellar mass ($M_\star =10^{9}-10^{11.5} M_\odot$) and redshift ($0.01<z<0.05$). This includes new Arecibo observations of 208 galaxies, for which we release catalogs and HI spectra. In addition to extending the GASS HI 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 $\log M_\star/M_\odot = 9$. Total gas reservoirs remain HI-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 $\mu_\star$, but individual values vary by almost two orders of magnitude at fixed $M_\star$ or $\mu_\star$. We show that, for galaxies on the star-forming sequence, variations of $R_{mol}$ are mostly driven by changes of the HI reservoirs, with a clear dependence on $\mu_\star$. 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 disk components for the study of gas scaling relations.

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astro-ph.GA 5

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2026 5

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representative citing papers

Resolved HI and Environmental Dynamics

astro-ph.GA · 2026-07-02 · unverdicted · novelty 2.0

SKA-mid AA4 will enable deep, spatially resolved HI imaging over hundreds of square degrees at column densities down to 10^18 cm^{-2} to study environmental gas processes from isolated galaxies to clusters.

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Showing 4 of 4 citing papers after filters.

  • Multiphase images of a powerful supernova-driven wind in the early Universe astro-ph.GA · 2026-06-09 · unverdicted · none · ref 235 · internal anchor

    Resolved multiphase observations reveal a supernova-driven wind in a z=5.3 galaxy removing gas at twice the star-formation rate, potentially quenching it within 100 Myr and matching local superwind properties.

  • MSA-3D: Rotation Curves and Dark Matter Fractions at z~0.5-1.7 with JWST/NIRSpec astro-ph.GA · 2026-06-26 · unverdicted · none · ref 258 · internal anchor

    New JWST data on 23 galaxies at 0.5<z<1.7 show median dark matter fraction of 0.63 at effective radius with 0.2 dex scatter, and a mix of rising, flat, and falling rotation curves.

  • Resolved HI and Environmental Dynamics astro-ph.GA · 2026-07-02 · unverdicted · none · ref 192 · internal anchor

    SKA-mid AA4 will enable deep, spatially resolved HI imaging over hundreds of square degrees at column densities down to 10^18 cm^{-2} to study environmental gas processes from isolated galaxies to clusters.

  • Cosmological Galaxy Formation Modelling in the Era of the Square Kilometre Array astro-ph.GA · 2026-06-24 · unverdicted · none · ref 45 · internal anchor

    Review of state-of-the-art cosmological galaxy formation models for HI, molecular gas and radio continuum in preparation for SKA, advocating coordinated multi-scale simulations, forward modelling and AI emulators.