[IAUC] CBET 3613: 20130802 : SUPERNOVA 2013en IN UGC 11369 = PSN J18513735+2338206

Vie Ago 2 11:18:23 ART 2013

                                                  Electronic Telegram No. 3613
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 2013en IN UGC 11369 = PSN J18513735+2338206
     F. Ciabattari, E. Mazzoni, and M. Rossi, Borgo a Mozzano, Italy, report
their discovery of an apparent supernova (mag 16.5) on unfiltered CCD images
(limiting magnitude 19.5) obtained on July 30.98 UT with a 0.5-m Newtonian
telescope in the course of the Italian Supernovae Search Project.  The new
object is located at R.A. = 18h51m37s.35, Decl. = +23d38'20".6 (equinox
2000.0; astrometry with respect to UCAC-2 stars), which is 6" west and 17"
north of the center of the galaxy UGC 11369.  Nothing is visible at this
position on the digitized plates of the Palomar Sky Survey from 1993 July 25
(F plate; limiting magnitude 20.3) and 1990 July 20 (J plate; limiting mag
20.3).  The variable was designated PSN J18513735+2338206 when it was posted
at the Central Bureau's TOCP webpage and is here designated SN 2013en based
on the spectroscopic confirmation reported below.  Additional CCD magnitudes
for 2013en:  2013 July 5, [19.5 (Ciabattari); July 15, 18.7 (Ciabattari; just
visible); July 31.954, 17.0 (Gianluca Masi and Francesca Nocentini, remotely
using a 43-cm telescope at Ceccano, Italy; position end figures 37s.31,
21".4); Aug. 1.041, 16.6 (Federica Luppi and Luca Buzzi, Varese, Italy; 0.36-m
f/7.1 reflector; position end figures 37s.31, 21".3; reference stars from the
CMC-14 catalogue; a knot or an H II region is visible in Digitized Sky Survey
images; image posted at URL http://www.astrogeo.va.it/pub/TOCP/PSN_U11369.jpg);
Aug. 1.342, 16.2 (L. Elenin, Lyubertsy, Russia, and I. Molotov, Moscow;
remotely taken with a 0.45-m f/2.8 telescope at the ISON-NM Observatory near
Mayhill, NM, USA; position end figures 37s.30 +/- 0".19, 21".0; UCAC-4
reference stars; limiting mag about 19.0; image posted at website URL
http://spaceobs.org/images/TOCP/PSNJ18513735+2338206-20130801.png).

     L. Tomasella, E. Cappellaro, S. Benetti, P. Ochner, A. Pastorello, and M.
Turatto, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica,
report that an optical spectrogram (range 340-820 nm; resolution 1.3 nm) of
PSN J18513735+2338206 = SN 2013en, obtained on July 31.84 UT with the Asiago
1.82-m Copernico Telescope (+ AFOSC), shows that 2013en is most likely a
peculiar type-Ia supernova.  Adopting for the host galaxy (UGC 11369) the
redshift z = 0.015207 (Falco et al. 1999, PASP 111, 438; via NED), a good
match is found with the type-Ia supernova 2005hk (Phillips et al. 2007, PASP
119, 360) near maximum.  The 2013en spectrum shows strong Na I D interstellar
absorptions, both the Galactic and host-galaxy components with similar
equivalent widths (about 0.15 nm).  The Galactic component is consistent with
the estimated dust extinction A_V about 0.8 mag (Schlafly and Finkbeiner 2011,
Ap.J. 737, 103; via NED).  A similar amount of additional extinction can be
expected in the host galaxy.  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).


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                         (C) Copyright 2013 CBAT
2013 August 2                    (CBET 3613)              Daniel W. E. Green