The Properties of Type Ia Supernova Host Galaxies from the Sloan Digital
  Sky Survey
  We investigate the properties and environments of Type Ia Supernova (SN Ia)
host galaxies in the Stripe 82 of the Sloan Digital Sky Survey-II Supernova
Survey centered on the celestial equator. Host galaxies are defined as the
galaxy nearest to the supernova (SN) in terms of angular distance whose
velocity difference from the SN is less than 1000 km s^{-1}. Eighty seven SN Ia
host galaxies are selected from the SDSS Main galaxy sample with the apparent
r-band magnitude m_r < 17.77, and compared with the SDSS Main galaxies. The SN
Ia rates for early and late-type galaxies are 0.81 +- 0.19 SN (100yr)^{-1} and
0.99 +- 0.21 SN (100yr)^{-1}, respectively. We find that the host galaxies have
a color distribution consistent with that of the Main galaxies, regardless of
their morphology. However, host galaxies are on average brighter than the Main
galaxies by ~ 0.3 mag over the range of -18.3 > M_r > -21.3. But the brighter
ends of their luminosity distributions are similar. The distribution of the
distance to the nearest neighbor galaxy shows that SNe Ia are more likely to
occur in isolated galaxies without close neighbors. We also find that the SN Ia
host galaxies are preferentially located in a region close to massive galaxy
clusters compared to the Main galaxies.
