MAGIICAT I. The MgII Absorber-Galaxy Catalog

We describe the MgII Absorber-Galaxy Catalog, MAGIICAT, a compilation of 182 spectroscopically identified intermediate redshift (0.07 0.3 Ang], low redshift (z zmed), where zmed = 0.359 is the median galaxy redshift. Rest-frame color B-K correlates with M_K at the 8 sigma level for the whole sample but is driven by the strong absorbing, high redshift subsample (6 sigma). Using M_K as a proxy for stellar mass and examining the luminosity functions, we infer that in lower stellar mass galaxies, MgII absorption is preferentially detected in blue galaxies and the absorption is more likely to be weak.