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 < z < 1.1) galaxies
with measurements of MgII 2796, 2803 absorption from their circumgalactic
medium within projected distances of 200 kpc from background quasars. In this
work, we present "isolated" galaxies, which are defined as having no
spectroscopically identified galaxy within a projected distance of 100 kpc and
a line of sight velocity separation of 500 km/s. We standardized all galaxy
properties to the Lambda CDM cosmology and galaxy luminosities, absolute
magnitudes, and rest-frame colors to the B- and K-band on the AB system. We
present galaxy properties and rest-frame MgII equivalent width, Wr(2796),
versus galaxy redshift. The well-known anti-correlation between Wr(2796) and
quasar-galaxy impact parameter, D, is significant to the 8 sigma level. The
mean color of MAGIICAT galaxies is consistent with an Sbc galaxy for all
redshifts. We also present B- and K-band luminosity functions for different
Wr(2796) and redshift subsamples: "weak absorbing" [Wr(2796) < 0.3 Ang],
"strong absorbing" [Wr(2796) > 0.3 Ang], low redshift (z < zmed), and high
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.
