Electronic Telegram No. 3577

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 2013ds IN PGC 57429 = PSN J16112958+5722517
     F. Ciabattari, E. Mazzoni, and S. Donati, Borgo a Mozzano, Italy, report
their discovery of an apparent supernova (mag 18.0) on unfiltered CCD images
(limiting magnitude 19.5) obtained on July 1.92 and 2.85 UT with a 0.5-m
Newtonian reflector in the course of the Italian Supernovae Search Project.
The new object is located at R.A. = 16h11m29s.58, Decl. = +57d22'51".7
(equinox 2000.0; astrometry with respect to USNO-B stars), which is 15" west
and 5" south of the center of the galaxy PGC 57429 = MCG +10-23-36.  Nothing
is visible at this position on digitized plates of the Palomar Sky Survey
from 1954 June 28 (E and O plates; limiting mag 20.1).  The variable was
designated PSN J16112958+5722517 when it was posted at the Central Bureau's
TOCP webpage and is here designated SN 2013ds based on the spectroscopic
confirmation reported below.  Additional CCD magnitudes for 2013ds:  2013
June 14, [19.2 (Ciabattari); July 4.934, V = 17.9 (Massimiliano Martignoni,
Magnago, Italy; 0.25-m f/10 Schmidt-Cassegrain reflector; position end figures
29s.53, 51".6); 5.389, 17.4 (Joseph Brimacombe, Cairns, Australia; remotely
with a 51-cm telescope + luminance filter at the New Mexico Skies observatory
near Mayhill, NM, U.S.A.; position end figures 29s.58, 52".0; image posted at
website URL http://www.flickr.com/photos/43846774@N02/9230355204/); 6.896,
R = 17.3 (Xavier Bros, Ager, Spain; 0.35-m telescope; position end figures
29s.55, 51".9; UCAC2 reference stars; image posted at the following website
URL:  http://www.anysllum.com/PSN_PGC57429.jpg).

     L. Tomasella, S. Benetti, A. Pastorello, E. Cappellaro, P. Ochner, and M.
Turatto, report that optical spectroscopy (range 340-820 nm; resolution 1.3
nm), obtained on July 2.89 UT with the Asiago 1.82-m Copernico Telescope (+
AFOSC), shows that PSN J16112958+5722517 = SN 2013ds is a core-collapse
supernova.  Assuming for the host galaxy a redshift of about 0.053 (which
agrees with the photometric redshift of 0.063 +/- 0.028 from the Sloan Digital
Sky Survey DR9), a fair match is found with a spectrum of SN 1993J soon after
explosion.  In general, the spectrum is consistent with those of early
type-II supernovae.  For a detailed classification, one must wait for the
supernova's aging data.  The Asiago classification spectra are posted at
website URL http://sngroup.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 July 10                     (CBET 3577)              Daniel W. E. Green





-- 
Xavier Bros
http://www.anysllum.com