The ALFALFA-SDSS Galaxy Catalog
  We present an HI-optical catalog of ~ 30,000 galaxies based on the 100%
complete Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) survey
combined with data from the Sloan Digital Sky Survey (SDSS). Our goal is to
facilitate public use of the completed ALFALFA catalog by providing carefully
determined matches to SDSS counterparts, including matches for ~ 12,000
galaxies that do not have SDSS spectra. These identifications can provide a
basis for further cross-matching with other surveys using SDSS photometric IDs
as a reference point. We derive absolute magnitudes and stellar masses for each
galaxy using optical colors combined with an internal reddening correction
designed for small- and intermediate-mass galaxies with active star formation.
We also provide measures of stellar masses and star formation rates based on
infrared and/or ultraviolet photometry for galaxies that are detected by the
Wide-field Infrared Survey Explorer (WISE) and/or the Galaxy Evolution Explorer
(GALEX). Finally, we compare the galaxy population in the ALFALFA-SDSS sample
with the populations in several other publicly-available galaxy catalogs, and
confirm that ALFALFA galaxies typically have lower masses and bluer colors.
