[IAUC] CBET 3399: 20130204 : SUPERNOVA 2013P IN MCG +05-22-20 = PSN J09133717+2959587

Lun Feb 4 12:48:46 ART 2013

                                                  Electronic Telegram No. 3399
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 2013P IN MCG +05-22-20 = PSN J09133717+2959587
     S. Howerton, Arkansas City, KS, U.S.A.; A. J. Drake, S. G. Djorgovski,
A. Mahabal, M. J. Graham, and R. Williams, California Institute of Technology;
J. L. Prieto, Princeton University; M. Catelan, Pontificia Universidad
Catolica de Chile; and E. C. Beshore, S. M. Larson, and E. Christensen, Lunar
and Planetary Laboratory, University of Arizona, report the discovery of an
apparent supernova in public images from the Catalina Sky Survey (CSS).

 SN      2013 UT        R.A. (2000.0) Decl.     Mag.      Offset
 2013P   Jan. 15.43   9 13 37.17  +29 59 58.7   17.0    2".3 W, 0".3 N

The variable was designated PSN J09133717+2959587 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2013P based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2013P:  Jan. 3.46 UT, [19.0 (CSS); 16.261, 16.0 (Joseph Brimacombe, Cairns,
Australia; remotely using a 51-cm RCOS telescope + luminance filter located at
the New Mexico Skies Observatory near Mayhill, NM, U.S.A.; image posted at
website URL http://www.flickr.com/photos/43846774@N02/8401340758/; position
end figures 37s.36, 58".6); 18.178, 16.3 (Federica Luppi and Luca Buzzi,
Varese, Italy; 0.38-m f/6.8 reflector; position end figures 37s.28, 58".5;
reference stars from CMC-14 catalogue; position and magnitude are highly
contaminated by the background light of the presumed host galaxy; image
posted at URL http://www.astrogeo.va.it/pub/TOCP/PSN_G05-22-20.jpg); 22.895,
R_c = 16.7 (Massimiliano Martignoni, Magnago, Italy; 0.5-m f/10 reflector;
position end figures 37s.36, 58".6).

     P. Ochner, Osservatorio Astronomico di Padova, Istituto Nazionale di
Astrofisica (OAPd-INAF); N. Blagorodnova, Institute of Astronomy, University
of Cambridge; and L. Tomasella, S. Benetti, E. Cappellaro, A. Pastorello, and
M. Turatto, OAPd-INAF, report that optical spectroscopy (range 340-800 nm;
resolution 0.7 nm), obtained on Jan. 29.86 UT with the Asiago 1.22-m Galileo
Telescope (+ Boller & Chivens spectrograph), shows that PSN J09133717+2959587
= SN 2013P is most likely a type-Ic supernova.  Adopting for the host galaxy
(MCG +05-22-20) the redshift z = 0.024537 (Mahdavi and Geller 2004, Ap.J. 607,
202; via NED), the best match is with the type-Ic supernova 2004aw
(Taubenberger et al. 2006, MNRAS 371, 1459) around maximum light.  The 2013P
spectrum shows very intense Na I D interstellar absorption (EW about 0.31
nm), which may suggest a significant reddening in the host galaxy and would
make for a very bright event.  When this high reddening is taken into account,
the best match is obtained with spectra of the type-IIb supernova 1993J
(Barbon et al. 1995, A.Ap. Suppl. 110, 513) at maximum light.  The Asiago
classification spectra are posted at website URL http://graspa.oapd.inaf.it;
classification was made via GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383)
and SNID (Blondin and Tonry 2007, Ap.J. 666, 1024).

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

                         (C) Copyright 2013 CBAT
2013 February 4                  (CBET 3399)              Daniel W. E. Green