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Date and Time of the Query: 2019-02-16 T10:24:45 PST
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For refcode 2015ApJ...809..146B:
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Copyright by American Astronomical Society. Reproduced by permission
2015ApJ...809..146B A Study in Blue: The Baryon Content of Isolated Low-mass Galaxies Bradford, Jeremy D.; Geha, Marla C.; Blanton, Michael R. Abstract. We study the baryon content of low-mass galaxies selected from the Sloan Digital Sky Survey (SDSS DR8), focusing on galaxies in isolated environments where the complicating physics of galaxy-galaxy interactions are minimized. We measure neutral hydrogen (HI) gas masses and line widths for 148 isolated galaxies with stellar mass between 10^7^ and {10}^9.5^{M}_sun_. We compare isolated low-mass galaxies to more massive galaxies and galaxies in denser environments by remeasuring HI emission lines from the Arecibo Legacy Fast ALFA survey 40% data release. All isolated low-mass galaxies either have large atomic gas fractions or large atomic gas fractions cannot be ruled out via their upper limits. We measure a median atomic gas fraction of {f}_{gas_}=0.81+/- 0.13 for our isolated low-mass sample with no systems below 0.30. At all stellar masses, the correlations between galaxy radius, baryonic mass, and velocity width are not significantly affected by environment. Finally, we estimate a median baryon to total dynamical mass fraction of {f}_{baryon_,{disk}}=0.15+/- 0.17. We also estimate two different median baryon to halo mass fractions using the results of semi-analytic models ({f}_{baryon_,{halo}}=0.04+/- 0.06) and abundance matching ({f}_{baryon_,{halo}}=0.04+/- 0.02). Baryon fractions estimated directly using HI observations appear independent of environment and maximum circular velocity, while baryon fractions estimated using abundance matching show a significant depletion of baryons at low maximum circular velocities. Key words: galaxies: dwarf, galaxies: evolution, galaxies: ISM, galaxies: kinematics and dynamics
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