Ca II and Na I Quasar Absorption-Line Systems in an Emission-Selected
  Sample of SDSS DR7 Galaxy/Quasar Projections: I. Sample Selection
  The aim of this project is to identify low-redshift host galaxies of quasar
absorption-line systems by selecting galaxies which are seen in projection onto
quasar sightlines. To this end, we use the Seventh Data Release of the Sloan
Digital Sky Survey (SDSS-DR7) to construct a parent sample of 97489
galaxy/quasar projections at impact parameters of up to 100 kpc to the
foreground galaxy. We then search the quasar spectra for absorption line
systems of Ca II and Na I within +- 500 km/s of the galaxy's velocity. This
yields 92 Ca II and 16 Na I absorption systems. We find that most of the Ca II
and Na I systems are sightlines through the Galactic disk, through High
Velocity Cloud complexes in our halo, or Virgo cluster sightlines. Placing
constraints on the absorption line rest equivalent width significance (>=3.0
sigma), the Local Standard of Rest velocity along the sightline (>= 345 km/s),
and the ratio of the impact parameter to the galaxy optical radius (<=5.0), we
identify 4 absorption line systems that are associated with low-redshift
galaxies at high confidence, consisting of two Ca II systems (one of which also
shows Na I), and two Na I systems. These 4 systems arise in blue, L_r^*
galaxies. Tables of the 108 absorption systems are provided to facilitate
future follow up.
