HI and Star Formation Properties of Massive Galaxies: First Results from
  the GALEX Arecibo SDSS Survey
  The GALEX Arecibo SDSS Survey (GASS) is an ambitious program designed to
investigate the cold gas properties of massive galaxies, a challenging
population for HI studies. Using the Arecibo radio telescope, GASS is gathering
high-quality HI-line spectra for an unbiased sample of ~1000 galaxies with
stellar masses greater than 10^10 Msun and redshifts 0.025 < z < 0.05,
uniformly selected from the SDSS spectroscopic and GALEX imaging surveys. The
galaxies are observed until detected or until a low gas mass fraction limit
(1.5-5%) is reached. We present initial results based on the first Data
Release, which consists of ~20% of the final GASS sample. We use this data set
to explore the main scaling relations of HI gas fraction with galaxy structure
and NUV-r colour, and show our best fit plane describing the relation between
gas fraction, stellar mass surface density and NUV-r colour. Interesting
outliers from this plane include gas-rich red sequence galaxies that may be in
the process of regrowing their disks, as well as blue, but gas-poor spirals.
