CSS111230:143658+163057: a Luminous Type Ic SN at z=0.245
ATel #3883; J. L. Prieto (Princeton), A. J. Drake, A. A. Mahabal, S. G. Djorgovski, M. J. Graham, R. Williams (Caltech), M. Catelan (PUC, Chile), E. Christensen (Gemini Obs.), E. C. Beshore, M. Larson (LPL/UA)
on 25 Jan 2012; 00:07 UT
Credential Certification: Jose L. Prieto (jose@obs.carnegiescience.edu)
Subjects: Optical, Supernovae, Transient
Referred to by ATel #: 4498
We report spectroscopic observations of CSS111230:143658+163057
discovered 2011, Dec 30.52 by CRTS (ATEL #3873). We obtained low-resolution
optical spectra of this supernova candidate on Jan 2.5 with the APO 3.5-m
telescope (+DIS) and on Jan 17.5 with the Palomar 200-inch telescope (+ Double
Spec). The spectra show a blue continuum and broad features consistent with
a supernova spectrum. We identify faint, unresolved emission lines present
in both spectra at 6233 and 8170 Angstroms, which are consistent with the
wavelengths of [O III] 5009 and Halpha from a star-forming host galaxy at
redshift z=0.245. Cross-correlation with a library of SN spectra using
SNID (Blondin & Tonry 2007, ApJ, 666, 1024) shows that the spectrum of
the transient is most similar to type Ic SNe. The discovery magnitude
of V=18.8 and host galaxy redshift z=0.245 (distance modulus mu = 40.3 mag),
imply that CSS111230:143658+163057 was quite luminous at the time of
discovery, with MV ~ -21.5 mag. There is no host galaxy detected in
pre-discovery SDSS images at the SN location, suggesting that
the host galaxy is an star-forming dwarf fainter than the LMC (abs.
mag > -18).
