[IAUC] CBET 3777: 20140111 : SUPERNOVA 2014C IN NGC 7331 = PSN J22370560+3424319

Vie Ene 10 22:29:07 ART 2014

                                                  Electronic Telegram No. 3777
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 2014C IN NGC 7331 = PSN J22370560+3424319
     Further to CBET 3772, M. Kim, W. Zheng, W. Li, and A. V. Filippenko,
University of California at Berkeley; and S. B. Cenko, Goddard Space Flight
Center, report the LOSS discovery of a supernova in NGC 7331 on unfiltered
KAIT images:

 SN       2014 UT       R.A. (2000.0) Decl.      Mag.      Offset
 2014C    Jan. 5.09   22 37 05.60  +34 24 31.9   15.5    19".7 E, 24".2 S

The supernova was also detected at red mag about 17.1 three days earlier on a
pre-discovery image taken on Jan. 2.10 UT.  A finding chart was posted at URL
http://astro.berkeley.edu/~zwk/findingchart/PSN_J22370560+34243193.jpg.  The
variable was designated PSN J22370560+3424319 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2014C based on the
spectroscopic confirmation reported below.  The type-II supernova 2013bu also
appeared in NGC 7331 (cf. CBET 3498).  Additional CCD magnitudes for 2014C:
2013 Dec. 26, [18.5 (KAIT); 2014 Jan. 4.861, 15.8 (Ron Arbour, South Wonston,
U.K.; 35-cm f/6 reflector; pre-discovery image; position end figures 05s.59,
31".3; offset 18" east, 25" south); 6.702, 15.3 (Gianluca Masi, Francesca
Nocentini, and Patrick Schmeer; remotely using a 43-cm telescope near Ceccano,
Italy; position end figures 05s.59, 31".4); 8.09, 14.5 (KAIT; measurement
after subtraction of background light).

     Jujia Zhang, Yunnan Observatories (YNAO); and Xiaofeng Wang, Tsinghua
University, report on an optical spectrogram (range 360-910 nm) of PSN
J22370560+3424319 = SN 2014C that was obtained on Jan. 5.54 UT with the 2.4-m
telescope (+ YFOSC) at the LiJiang Gaomeigu Station of the YNAO.  The spectrum
is consistent with a young type-Ib supernova.  Strong Na I D lines in the
spectra indicates that this supernova suffers a significant line-of-sight
reddening.  Cross-correlation with a library of supernova spectra using the
"Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666,
1024) shows that 2014C matches with SN 1999ex at -6 days.  Adopting a
recession velocity of 816 km/s for the host galaxy, NGC 7331 (Springob 2005,
Ap.J. Supp. 160, 149), they measure a velocity of the He 587.6-nm absorption
feature to be about 13800 km/s and a velocity of the Si II 635.5-nm
absorption to be about 9900 km/s.

     L. Tartaglia, A. Pastorello, S. Benetti, E. Cappellaro, L. Tomasella, P.
Ochner, N. Elias-Rosa, 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 J22370560+3424319 = SN 2014C, obtained
on Jan. 8.32 UT with the Asiago 1.82-m Copernico Telescope (+ AFOSC), shows
that this is a type-Ib supernova.  Adopting for the host galaxy (NGC 7331) a
redshift z = 0.00272 (Springob et al. 2005, Ap.J. Suppl. 160, 149; via NED),
good matches are obtained with the type-Ib supernovae 1999dn (Benetti et al.
2011, MNRAS 411, 2726) and 1999ex (Hamuy et al. 2002, A.J. 124, 417) at around
maximum light.  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 2014 CBAT
2014 January 11                  (CBET 3777)              Daniel W. E. Green