Gas, Stars and Star Formation in ALFALFA Dwarf Galaxies
S. Huang, M.P. Haynes, R. Giovanelli, J. Brinchmann, S. Stierwalt,, S.G. Neff

TL;DR
This study analyzes the properties of low HI mass dwarf galaxies from ALFALFA, revealing their star formation behaviors, gas content, and how they compare to global star formation laws, with implications for galaxy evolution.
Contribution
It provides a comprehensive analysis of the stellar and HI components of ALFALFA dwarf galaxies, highlighting their star formation rates, gas fractions, and depletion timescales, which were not previously characterized in detail.
Findings
Many dwarfs have high SSFRs and short HI depletion timescales.
SED-based SFRs are systematically smaller than standard estimates.
Gas-rich galaxies have lower star formation efficiencies.
Abstract
We examine the global properties of the stellar and HI components of 229 low HI mass dwarf galaxies extracted from the ALFALFA survey, including a complete sample of 176 galaxies with HI masses < 10^{7.7} M_sun and HI line widths < 80 km s^{-1}. SDSS data are combined with photometric properties derived from GALEX to derive stellar masses (M_*) and star formation rates (SFRs) by fitting their UV-optical spectral energy distributions (SEDs). In optical images, many of the ALFALFA dwarfs are faint and of low surface brightness; only 56% of those within the SDSS footprint have a counterpart in the SDSS spectroscopic survey. A large fraction of the dwarfs have high specific star formation rates (SSFRs) and estimates of their SFRs and M_* obtained by SED fitting are systematically smaller than ones derived via standard formulae assuming a constant SFR. The increased dispersion of the SSFR…
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Taxonomy
TopicsGalaxies: Formation, Evolution, Phenomena · Astronomy and Astrophysical Research · Stellar, planetary, and galactic studies
