[IAUC] CBET 2461: 20100919 : SUPERNOVAE 2010hs, 2010hw, AND 2010hy

[quai en eps.harvard.edu]

                                                  Electronic Telegram No. 2461
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 en eps.harvard.edu (alternate cbat en iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


SUPERNOVAE 2010hs, 2010hw, AND 2010hy
     Further to CBET 2458, J. Kodros, S. B. Cenko, W. Li, and A. V. Filippenko,
University of California, report the LOSS discovery of an apparent supernova
on unfiltered KAIT images:

   SN       2010 UT        R.A. (2000.0) Decl.      Mag.
   2010hy   Sept. 4.19   18 59 32.89  +19 24 25.9   19.1

Additional KAIT magnitudes for 2010hy:  a co-added frame from May-July,
[20.5; Sept. 5.22 UT, 19.1.  SN 2010hy is located 50" west and 73" south
of UGC 11385, but the spectrum (see below) appears to indicate that it is
located in a background galaxy at significantly higher redshift.

     S. B. Cenko, M. T. Kandrashoff, J. M. Silverman, and A. V. Filippenko,
University of California, Berkeley, report that inspection of CCD spectra
(range 340-1000 nm), obtained on Sept. 16 UT with the 3-m Shane reflector (+
Kast) at Lick Observatory, shows that 2010hy is a supernova, perhaps of type
Ic near maximum brightness, but the possibility that 2010hy is actually a
type-Ia supernova cannot be ruled out.  The observed brightness, together with
the derived redshift of about 0.2 (from the supernova features), implies an
absolute visual magnitude of roughly -21, which is highly overluminous for
type-Ia and type-Ic supernovae.  Higher quality spectra, as well as
continued photometry, should be obtained.  Inspection of similar CCD spectra
shows that 2010hs (CBET 2454) is a type-Ia supernova; cross-correlation with a
library of supernova spectra using the "SuperNova IDentification" code (SNID;
Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2010hs is near
maximum brightness.  A noisy spectrum of 2010hw (CBET 2458) shows that it is a
type-II supernova.


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                         (C) Copyright 2010 CBAT
2010 September 19                (CBET 2461)              Daniel W. E. Green