The RESOLVE Survey Atomic Gas Census and Environmental Influences on Galaxy Gas Content
Abstract
We present the >93% complete 21cm inventory for the RESOLVE survey, a volume-limited census of ~1500 galaxies spanning diverse environments and probing baryonic masses down to ~109 M⊙. A key strength of the 21cm observational program is its fractional mass limited design, which yields an unbiased inventory of atomic gas mass, with either clean detections or strong upper limits <5-10% of stellar mass. We combine this gas census with metrics that parameterize environment from group scales (group dark matter halo mass) up to large-scale structure (mass density of the cosmic web and classification into filaments, walls, and voids) to investigate the influence of small and large-scale environment on galaxy gas content. We show that satellites in groups down to 1012 M⊙ have lower gas fractions compared to centrals at similar stellar mass, suggesting that group processes that deplete gas content are active well below the large group/cluster scale. In addition, at fixed halo mass both centrals and satellites in large-scale walls have systematically lower gas fractions than galaxies in filaments or voids, and this trend cannot be fully explained by differing stellar mass distributions within these large-scale environments. Lastly, we show that the abundance of gas-poor (gas-to-stellar mass ratio < 0.1) low halo-mass (<1011.4 M⊙) centrals increases with large-scale structure density, and that these centrals tend to reside closer to the outskirts of >1012 M⊙ groups than do more gas-rich but otherwise analogous low halo-mass centrals, suggesting that the gas-poor centrals have lost their gas in flyby interactions with the nearby groups. We discuss how the observed trends may be shaped by a number of physical processes such as gas stripping, starvation, and halo assembly bias. This project has been supported by NSF funding for the RESOLVE survey (AST-0955368), the GBT Student Observing Support program, and a UNC Royster Society of Fellows Dissertation Completion Fellowship.
- Publication:
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American Astronomical Society Meeting Abstracts #227
- Pub Date:
- January 2016
- Bibcode:
- 2016AAS...22731105S