GALEX ToO UV Spectroscopy of Nearby Core-Collapse SNe
Latest results (1): GALEX spectroscopy of SN 2005ay in NGC 3938
Comparison with HST spectra of SN 1999em and Swift/UVOT spectra of SN 2005cs shows a remarkable similarity; the combined imformation from these three events now allow to trace the UV spectral evolution of SNe II-P during the first month after explosion; from Gal-Yam et al. 2008.
Latest results (2): GALEX observations of our latest ToO target, SN 2008aw:
This interesting object (transition between type II-P and II-L) was well detected
by GALEX. This observational campaign is still underway.
Motivation:
Supernova (SN) explosions play a pivotal role in triggering, driving, and
(later on) inhibiting further star formation in galaxies. In fact, the combination
of new observations and refined modelling shows that the little-understood and
poorly constrained contribution of SNe to galaxy evolution processes (often
hidden under the generic name of ``feedback'') is probably the weakest link
in our understanding of structure formation in the Universe. Setting observational
limits on the rate, environments, and energy output of high-redshift SNe is
therefore one of the main science drivers of recent Hubble Space Telescope (HST)
legacy programs, as well as of future missions like the James Webb Space
Telescope (JWST). However, observations of high-redshift SNe in the optical
(by HST), or in the near-IR (by JWST), actually sample the rest-frame UV of
these objects. Thus, proper interpretation of these observations requires
knowledge about the UV properties of SNe. Unfortunately, UV spectroscopy of
local SNe of all types, which can only be obtained from space, is almost
non-existent. Such UV data are also powerful probes of the SN environment,
progenitor structure and explosion physics.
We have
been pursuing a GALEX program (cycles 1-4; PI Gal-Yam)
to obtain target-of-opportunity
GALEX spectroscopic observations of nearby, bright non-Ia (core-collapse) SNe.
Accumulated data (4 events observed so far, see below
lead towards a full characterization
of the UV spectral evolution of SNe of all types.
