The RESOLVE Survey Atomic Gas Census and Environmental Influences on Galaxy Gas Reservoirs

TL;DR

This study provides a comprehensive atomic gas census of over 1500 local galaxies, revealing how environment influences gas content and galaxy evolution, with evidence of environmental effects like stripping and starvation.

Contribution

It offers the first large-scale, volume-limited HI mass inventory for the RESOLVE survey and analyzes environmental impacts on galaxy gas reservoirs in detail.

Findings

Satellites show decreasing G/S with increasing halo mass starting at 10^12 Msun.

Gas-poor centrals increase with large-scale structure density.

Environmental effects like stripping and starvation are evident in galaxy gas content.

Abstract

We present the HI mass inventory for the RESOLVE survey, a volume-limited, multi-wavelength census of >1500 z=0 galaxies spanning diverse environments and complete in baryonic mass down to dwarfs of 10^9 Msun. This first 21cm data release provides robust detections or strong upper limits (1.4M_HI < 5 to 10% of stellar mass M_stars) for 94% of RESOLVE. We examine global atomic gas-to-stellar mass ratios (G/S) in relation to galaxy environment using several metrics: group dark matter halo mass M_h , central/satellite designation, relative mass density of the cosmic web, and distance to nearest massive group. We find that at fixed M_stars, satellites have decreasing G/S with increasing M_h starting clearly at M_h = 10^12 Msun, suggesting the presence of starvation and/or stripping mechanisms associated with halo gas heating in intermediate-mass groups. The analogous relationship for centrals is uncertain because halo abundance matching builds in relationships between central G/S, stellar mass, and halo mass, which depend on the integrated group property used as a proxy for halo mass (stellar or baryonic mass). On larger scales G/S trends are less sensitive to the abundance matching method. At fixed M_h < 10^12 Msun, the fraction of gas-poor centrals increases with large-scale structure density. In overdense regions, we identify a rare population of gas-poor centrals in low-mass (M_h < 10^11.4 Msun) halos primarily located within 1.5 times the virial radius of more massive (M_h > 10^12 Msun) halos, suggesting that gas stripping and/or starvation may be induced by interactions with larger halos or the surrounding cosmic web. We find that the detailed relationship between G/S and environment varies when we examine different subvolumes of RESOLVE independently, which we suggest may be a signature of assembly bias.