Electronic Telegram No. 2565
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


SUPERNOVAE 2010kc AND 2010kg
     J. M. Silverman, S. B. Cenko, M. T. Kandrashoff, and A. V. Filippenko,
University of California, Berkeley, report that inspection of a CCD spectrum
(range 340-1000 nm), obtained on Nov. 30 UT with the 3-m Shane reflector (+
Kast) at Lick Observatory, shows that 2010kc (CBET 2552) is a type-Ib
supernova.  SN 2010kg (CBET 2561) is a very young type-Ia supernova.  After
removal of the host-galaxy recession velocity of 4770 km/s (measured from
their own spectrum of the host, NGC 1633), they find the absorption minimum
of the Si II 635.5-nm line to be blueshifted by about 21300 km/s.  Cross-
correlation with a library of supernova spectra using the "SuperNova
IDentification" code (SNID; Blondin and Tonry 2007, Ap.J.  666, 1024)
indicates that 2010kg is a normal type-Ia supernova (consistent with the
findings of Marion et al., CBET 2561) and might be as young as 10-14 days
before maximum brightness.  Extensive follow-up observations are encouraged.

     G. H. Marion, Harvard-Smithsonian Center for Astrophysics (CfA), on
behalf of the CfA Supernova Group; and D. Griep, NASA Infrared Telescope
Facility (IRTF), report that a near-infrared spectrum (range 700-2400 nm) of
SN 2010kg (cf. CBET 2561) was obtained on Dec 3.4 UT with the SpeX instrument
on the IRTF 3.0-m telescope.  The spectrum exhibits unusually high velocities
with lines from O I, Mg II, and Si II found between 18000 and 20000 km/s.
The Ca II infrared triplet (857.9 mn) is exceptional strong, and the
absorption-line profile has a square bottom with the blue side near 32000
km/s and the red side near 26000 km/s.  The blue wings of the Ca II feature
extend to at least 40000 km/s, where they blend with O I and Si II.  Possible
identifications are made for Si III and Fe III.  CI is not observed.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2010 CBAT
2010 December 4                  (CBET 2565)              Daniel W. E. Green