Electronic Telegram No. 3508
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


SUPERNOVA 2013ca IN PGC 37698 = PSN J11584325+1908562
     Kaicheng Zhang, Xiaofeng Wang, Li Zhou, and Juncheng Chen, Tsinghua
University (THU), China; Tianmeng Zhang and Xu Zhou, National Astronomical
Observatories of China (NAOC), report the discovery of an apparent supernova
(mag 18.1) on unfiltered CCD images taken on May 1.54 UT using the 0.6-m NAOC
Schmidt telescope in the course of the THU-NAOC Transient Survey (TNTS).  The
new object is located at R.A. = 11h58m43s.25, Decl. = +19d08'56".2 (equinox
2000.0), which is 4".3 east and 7".0 south of the center of the galaxy PGC
37698.  Nothing is visible at this position on a Digitized Sky Survey image
from the Palomar Sky Survey.  The TNTS images are posted at the following
URL:  http://www.thca.tsinghua.edu.cn/~wangxf/TNTS/PSNJ11584324+1908562.png.
The variable was designated PSN J11584325+1908562 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2013ca based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2013ca:  Apr. 10, [20.0 (TNTS); May 3.186, 17.7 (R. A. Koff, Bennett, CO,
USA; Meade 0.25-m f/10 reflector + Apogee U-47 camera; limiting magnitude
20.7; position end figures 43s.19, 55".4; image posted at website URL
http://antelopehillsobservatory.org/SNpictures/PSNJ11584325+1908562final.jpg);
3.309, 18.3 (Joseph Brimacombe, Cairns, Australia; remotely using a 51-cm RCOS
telescope + STL11K camera + luminance filter located at the New Mexico Skies
observatory near Mayhill, NM, U.S.A.; position end figures 43s.25, 55".5;
image posted at URL http://www.flickr.com/photos/43846774@N02/8705209087/).

     J. M. Silverman, University of Texas; J. Vinko, University of Szeged; R.
Quimby, Kavli IPMU, University of Tokyo; and J. C. Wheeler and E. Chatzopoulos,
University of Texas, write that a spectrogram, obtained on May 4.28 UT with
the 9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by
S. Rostopchin, shows that PSN J11584325+1908562 = SN 2013ca is a type-II
supernova.  Correlation with a library of supernova spectra using the
"SuperNova IDentification" code (SNID; Blondin and Tonry 2007, Ap.J. 666,
1024) indicates that 2013ca is a normal type-IIP supernova a couple days
after maximum brightness.  After removal of the host-galaxy recession
velocity of 13334 km/s (from narrow emission lines), the absorption minimum
of the H-alpha line is found to be blueshifted by about 8200 km/s.  They
also note that the continuum is quite blue and that the H-alpha emission
component greatly dominates over the absorption component.

     Jinghua Gao, Kaicheng Zhang and Xiaofeng Wang, Tsinghua University; and
Tianmeng Zhang, NAOC, report on an optical spectrogram (range 350-800 nm) of
PSN J11584325+1908562 = SN 2013ca that was obtained on May 3.7 UT with the
2.16-m telescope (+ BFOSC) at the Xinglong Station of the NAOC.  The spectrum
is consistent with a type II-P supernova a few days after maximum light.
Cross-correlation with a library of supernova spectra using the "Supernova
Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows
that 2013ca matches with the spectrum of the type-IIP supernova 2004et at +6
days.


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

                         (C) Copyright 2013 CBAT
2013 May 9                       (CBET 3508)              Daniel W. E. Green