[IAUC] CBET 2721: 20110513 : SUPERNOVA 2011cj IN UGC 9356 = PSN J14325381+1135493

[quai en eps.harvard.edu]

                                                  Electronic Telegram No. 2721
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


SUPERNOVA 2011cj IN UGC 9356 = PSN J14325381+1135493
     Further to CBET 2712, G. Li, S. B. Cenko, W. Li, and A. V. Filippenko
report the LOSS/KAIT discovery of an apparent supernova on unfiltered KAIT
images:

 SN       2011 UT       R.A. (2000.0) Decl.      Mag.      Offset
 2011cj   May 9.39    14 32 53.81  +11 35 49.3   17.0    4".4 E, 7".5 N

Nothing was visible at this position on a KAIT image taken on May 5.39 UT
(limiting mag 18.5).  This variable was designated PSN J14325381+1135493
when posted on the Central Bureau's TOCP webpage and is here designated
SN 2011cj based on the spectroscopic reports below.

     G. H. Marion, Harvard-Smithsonian Center for Astrophysics and University
of Texas; J. Vinko, University of Szeged; and J. C. Wheeler, University of
Texas, report that a spectrum (range 430-1000 nm) of PSN J14325381+1135493 =
SN 2011cj was obtained by J. Caldwell on May 12 UT with the 9.2-m Hobby-Eberly
Telescope (+ Marcario Low-Resolution Spectrograph).  Cross-correlation with a
library of supernova spectra using the "Supernova Identification" code (SNID;
Blondin and Tonry 2007, Ap.J. 666, 1024) shows that 2011cj is a type-IIP
supernova near maximum brightness.

     J. M. Silverman, A. V. Filippenko, and W. Li, University of California,
Berkeley, report that inspection of a CCD spectrum (range 340-1000 nm),
obtained by K. Hiner (University of California, Riverside) and A. Diamond-
Stanic (University of California, San Diego) on May 11 UT with the 3-m Shane
reflector (+ Kast) at Lick Observatory, shows that PSN J14325381+1135493 =
SN 2011cj is a very young type-II supernova.  The broad H-alpha emission
component has a substantially blueshifted centroid and greatly dominates over
the absorption component, and the continuum is quite blue.  There appears to
be broad, weak emission in the range 450-470 nm (blending with H-beta emission
around 480 nm), probably corresponding to C III/N III and He II, as is
commonly seen in Wolf-Rayet stars and in some other very young type-II
supernovae (e.g., SN 1998S; Leonard et al. 2000, Ap.J. 536, 239).  However,
unlike the case of SN 1998S, there is no clear evidence for an intermediate-
width or narrow component, so the object is not a type-IIn evemt at this
stage.  After removal of the host-galaxy recession velocity of 2300 km/s,
determined from narrow emission lines, the absorption minimum of the H-alpha
line is found to be blueshifted by 16000 km/s.


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

                         (C) Copyright 2011 CBAT
2011 May 13                      (CBET 2721)              Daniel W. E. Green