Core-Collapse Supernovae and Host Galaxy Stellar Populations
  We have used images and spectra of the Sloan Digital Sky Survey to examine
the host galaxies of 519 nearby supernovae. The colors at the sites of the
explosions, as well as chemical abundances, and specific star formation rates
of the host galaxies provide circumstantial evidence on the origin of each
supernova type. We examine separately SN II, SN IIn, SN IIb, SN Ib, SN Ic, and
SN Ic with broad lines (SN Ic-BL). For host galaxies that have multiple
spectroscopic fibers, we select the fiber with host radial offset most similar
to that of the SN. Type Ic SN explode at small host offsets, and their hosts
have exceptionally strongly star-forming, metal-rich, and dusty stellar
populations near their centers. The SN Ic-BL and SN IIb explode in
exceptionally blue locations, and, in our sample, we find that the host spectra
for SN Ic-BL show lower average oxygen abundances than those for SN Ic. SN IIb
host fiber spectra are also more metal-poor than those for SN Ib, although a
significant difference exists for only one of two strong-line diagnostics. SN
Ic-BL host galaxy emission lines show strong central specific star formation
rates. In contrast, we find no strong evidence for different environments for
SN IIn compared to the sites of SN II. Because our supernova sample is
constructed from a variety of sources, there is always a risk that sampling
methods can produce misleading results. We have separated the supernovae
discovered by targeted surveys from those discovered by galaxy-impartial
searches to examine these questions and show that our results do not depend
sensitively on the discovery technique.
