Electronic Telegram No. 3440
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 2013am IN M65 = PSN J11185695+1303494
     S. Nakano, Sumoto, Japan, reports the discovery by Matsuo Sugano
(Ogami-cho, Kakogawa, Hyogo-ken, Japan) of an apparent supernova (mag 15.6;
measured by K. Kadota, Ageo, Japan) on a unfiltered CCD frames taken on
Mar. 21.637 UT (and an hour later) using a 0.35-m f/11 Schmidt-Cassegrain
telescope (+ Bitran BJ-42L camera).  Kadota has measured the following
position for the variable from Sugano's frames (average value from four
frames):  R.A. = 11h18m56s.95, Decl. = +13d03'49".4 (equinox 2000.0), which is
15" east and 102" south of the center of the galaxy NGC 3623 = M65.  Sugano
writes that nothing is visible at this position on a frame taken on 2012 Dec.
10 (no limiting mag provided).  The variable was designated PSN
J11185695+1303494 when it was posted at the Central Bureau's TOCP webpage
and is here designated SN 2013am based on the spectroscopic confirmation
reported below.  Additional unfiltered CCD magnitudes for 2013am:  Mar.
22.116, 16.4 (Federica Luppi and Luca Buzzi, Varese, Italy; 0.38-m f/6.8
reflector; position end figures 56s.93, 50".1; reference stars from CMC-14
catalogue; image posted at URL http://www.astrogeo.va.it/pub/TOCP/PSN_M65.jpg);
22.744, 15.8 (Toshihide Noguchi, Katori, Chiba-ken, Japan; position end
figures 56s.93, 49".3; offset 15".3 east, 103".2 south; limiting mag 17.0;
0.23-m f/6.3 Schmidt-Cassegrain reflector + BITRAN BT-11E camera; UCAC3
reference stars; communicated by Nakano; image posted at website URL
http://park8.wakwak.com/~ngc/images/PSNinM65.jpg); 22.809, 16.4 (Gianluca Masi
and Stefano Giovanardi, Ceccano, Italy; 43-cm f/6.8 robotic unit part of the
Virtual Telescope Project; reference stars from UCAC-4 catalogue; position end
figures 56s.92, 50".0).

     S. Benetti, L. Tomasella, A. Pastorello, E. Cappellaro, M. Turatto, and
P. Ochner, Osservatorio Astronomico di Padova, Istituto Nazionale di
Astrofisica, report that a noisy optical spectrogram (range 340-820 nm;
resolution 1.3 nm), obtained on Mar. 22.84 UT with the Asiago 1.82-m Copernico
Telescope (+ AFOSC) by the Service Telescope Operating Team, shows that PSN
J11185695+1303494 = SN 2013am is a young (few days after explosion) type-II
supernova.  The spectrum shows a red continuum with broad (FWHM about 11000
km/s), asymmetric H-alpha emission and H-beta with a P-Cyg profile.  From the
H-beta minimum, an expansion velocity of about 9000 km/s is derived, assuming
a recession velocity of 807 km/s (from RC3, de Vaucouleurs et al. 1991; via
NED) for M65.  Since the missing detection of significant metal lines suggests
an early phase for the supernova, the red spectral continuum probably results
from significant line-of-sight extinction.  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 March 23                    (CBET 3440)              Daniel W. E. Green