UV Properties of Type Ia Supernova and their Host Galaxies
  Type Ia Supernova(SN Ia) are a powerful, albeit not completely understood,
tool for cosmology. Gaps in our understanding of their progenitors and detailed
physics can lead to systematic errors in the cosmological distances they
measure. We use UV data in two context to help further our understanding of SN
Ia progenitors and physics. We analyze a set of nearly 700 light curves, and
find no signature of the shock heating of a red giant companion, predicted by
Kasen (2010), casting doubt as to frequency of this SN Ia channel. We also use
UV imaging of high redshift host galaxies of SN Ia to better understand the
environments which SN Ia occur. We show that some high-z elliptical galaxies
have current star formation, hindering efforts to use them as low-extinction
environments. We show cosmological scatter of SN distances at large effective
radii in their hosts is significantly reduced, and argue this is due to the
smaller amounts of dust affecting the SN Ia. Finally, we find a two component
dependance of SN distance measurements as a function of their host galaxy's
FUV-V color. This indicates that both the age and metallicity/mass of the host
galaxy maybe important ingredients in measuring SN Ia distances.
