Data from: Angular momentum-related probe of cold gas deficiencies

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Recent studies of neutral atomic hydrogen (H I) in nearby galaxies found that all field disc galaxies are H I saturated, in that they carry roughly as much H I as permitted before this gas becomes gravitationally unstable. By taking this H I saturation for granted, the atomic gas fraction fatm of galactic discs can be predicted as a function of the stability parameter q = jσ/(GM), where Mand jare the baryonic mass and specific angular momentum of the disc and σ is the H I velocity dispersion (Obreschkow et al. 2016). The log-ratio Δfq between this predictor and the observed atomic fraction can be seen as a physically motivated ‘H I deficiency’. While field disc galaxies have Δfq ≈ 0, objects subject to environmental removal of H I are expected to have Δfq > 0. Within this framework, we revisit the H I deficiencies of satellite galaxies in the Virgo cluster and in clusters of the EAGLE simulation. We find that observed and simulated cluster galaxies are H I deficient and that Δfq slightly increases when getting closer to the cluster centres. The Δfq values are similar to traditional H I deficiency estimators, but Δfq is more directly comparable between observations and simulations than morphology-based–deficiency estimators. By tracking the simulated H I deficient cluster galaxies back in time, we confirm that Δfq ≈ 0 until the galaxies first enter a halo with Mhalo > 1013M☉, at which moment they quickly lose H I by environmental effects. Finally, we use the simulation to investigate the links between Δfq and quenching of star formation.

Notes

External Organisations
Centre for Astrophysics and Supercomputing

Associated Persons
Jie Li (Creator); Charlotte Welker (Creator)Robert Džudžar (Creator)