Electronic Telegram No. 2323
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Room 209; Dept. of Earth and Planetary
 Sciences; Harvard University; 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbat@iau.org; cbatiau@eps.harvard.edu
URL http://www.cfa.harvard.edu/iau/cbat.html


SUPERNOVAE 2010cs, 2010ct, 2010du, AND 2010eb
     J. M. Silverman, S. B. Cenko, D. Poznanski, and A. V. Filippenko,
University of California, Berkeley, report that inspection of CCD spectra
(range 350-1000 nm), obtained on June 12 UT with the 10-m Keck I telescope
(+ LRIS), shows that 2010cs (CBET 2284) is a type-Ia supernova.  Cross-
correlation with a library of supernova spectra using the "SuperNova
IDentification" code of Blondin and Tonry (2007, Ap.J. 666, 1024)
indicates that 2010cs is about one month past maximum brightness.  SN 2010ct
(CBET 2285) is a type-II supernova, probably of the IIP subtype and roughly
one month after the explosion; H-alpha exhibits a well-developed P-Cyg
profile; after removal of the host-galaxy recession velocity of 8300 km/s,
determined from narrow emission features, the absorption minimum of the
H-alpha line is found to be blueshifted by about 6400 km/s.  SN 2010du (CBET
2308) is also a type-II supernova, probably a type-IIP event roughly one
month after the explosion; its spectrum is very similar to that of SN
2010ct.  A CCD spectrum obtained in bright twilight, and only over the
wavelength range 350-560 nm, indicates that 2010eb (CBET 2321) is a
supernova, probably of type Ia and more than 1 month past maximum brightness.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2010 CBAT
2010 June 13                     (CBET 2323)              Daniel W. E. Green