Dust Extinction and Metallicities of Star-Forming Lyman Alpha Emitting
  Galaxies at Low Redshift
  We present the results of an optical spectroscopic study of 12
GALEX-discovered star-forming Lyman alpha emitting galaxies (LAEs) at z ~ 0.3.
We measure the emission line fluxes from these galaxies by fitting their
observed spectra to stellar population models in order to correct for
underlying stellar absorption. We revisit earlier stellar population model
fitting results, finding that excluding now-known AGNs lowers the typical
stellar population age and stellar mass of this sample to ~ 300 Myr and ~ 4 x
10^9 Msol, respectively. We calculate their dust extinction using the Balmer
decrement, and find a typical visual attenuation of Av ~ 0.3 mag, similar to
that seen in many high-redshift LAEs. Comparing the ratio of Lyalpha/Halpha and
the Lyman alpha equivalent widths to the measured dust extinction, we find that
the ISMs in these objects appear to be neither enhancing nor seriously
attenuating the Lyman alpha equivalent widths, as would be the case in a
quasi-clumpy ISM. Lastly, we perform a detailed analysis of the gas-phase
metallicities of these galaxies, and we find that most galaxies in our sample
have Z < 0.4 Zsol. We find that at a fixed stellar mass, these low-redshift LAE
analogs are offset by ~ 0.6 dex lower in metallicity from the general galaxy
population at similar redshifts based on the local mass-metallicity
relationship. This implies that galaxies with Lyman alpha in emission may be
systematically more metal poor than star-forming galaxies at the same stellar
mass and redshift, similar to preliminary results at z ~ 2.
