Electronic Telegram No. 2360
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 2010ej AND 2010em
     J. M. Silverman, S. B. Cenko, D. Perley, A. Cucchiara, J. S. Bloom,
and A. V. Filippenko, University of California, Berkeley, report that
inspection of CCD spectra (range 350-1000 nm), obtained on July 7 UT
with the 10-m Keck I telescope (+ LRIS), shows that 2010ej (CBET 2329) is a
type-II supernova.  After removal of the host-galaxy recession velocity of
15700 km/s, determined by narrow emission lines, it is found that the
absorption minimum of the H-alpha line is blueshifted by about 13000 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 2010ej is possibly a type-IIb supernova near maximum brightness
(which means that the supernova was discovered shortly after explosion).
SN 2010em (CBET 2335) is also a type-II supernova; after removal of the
host-galaxy recession velocity of 8300 km/s, determined by narrow emission
lines, it is found that the absorption minimum of the H-alpha line is
blueshifted by about 7500 km/s.  SNID indicates that 2010em is 1 to 2 months
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      superseded by text appearing later in the printed IAU Circulars.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 July 10                     (CBET 2360)              Daniel W. E. Green