[IAUC] CBET 3730: 20131129 : SUPERNOVA 2013gq IN NGC 2554 = PSN J08175346+2328105

Vie Nov 29 09:36:37 ART 2013

                                                  Electronic Telegram No. 3730
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 2013gq IN NGC 2554 = PSN J08175346+2328105
     [Editor's note:  this replaces the text on CBET 3729 (designation)]
     Further to CBET 3422, K. Blanchard, W. Zheng, S. B. Cenko, W. Li, and A.
V. Filippenko report the LOSS discovery of an apparent supernova in NGC 2554
on unfiltered KAIT images:

 SN       2013 UT       R.A. (2000.0) Decl.      Mag.      Offset
 2013gq   Mar. 25.19   8 17 53.46  +23 28 10.5   15.1    0".6 W, 9".1 S

A finding chart for the variable was posted at the following website URL:
http://astro.berkeley.edu/~zwk/findingchart/PSN_J08175346+2328105.jpg.  The
variable was designated PSN J08175346+2328105 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2013gq based on the
spectroscopic confirmation reported below.  Additional magnitudes for 2013gq:
Mar. 13.19 UT, [18.5 (KAIT); 25.887, V = 15.2 (Johan Warell, Skurup, Sweden;
25-cm reflector + SXV-H9 camera; photometry uncertain due to closeness of
variable to the core of NGC 2554; scale 2".23/pixel; position end figures
53s.51, 11".2; USNO-B1 reference stars); 25.895, R = 13.6 (Warell; position
end figures 53s.49, 11".7); 26.119, 15.4 (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 53s.54 +/- 0".08,
11".3 +/- 0".06; UCAC-4 reference stars; limiting mag about 18.8; image
posted at http://spaceobs.org/images/TOCP/PSNJ08175346+2328105-20130326.png);
26.32, 15.1 (KAIT; also, R magnitude around 15.0); 27.115, 14.8 (Joseph
Brimacombe, Cairns, Australia; remotely using a 51-cm RCOS telescope + STL11K
camera at the New Mexico Skies observatory near Mayhill, NM; infrared filter,
bandpass > 700 nm; position end figures 53s.53, 10".7; image posted at URL
http://www.flickr.com/photos/43846774@N02/8599691309/); 31.857, 14.7 (S.
Foglia and G. Galli, Pogliano Milanese, Italy; 0.28-m f/6.8 Schmidt-Cassegrain
reflector + ST8XME camera; position end figures 53s.51, 10".4; UCAC-4
reference stars); 31.929, 14.6 (Federica Luppi and Luca Buzzi, Varese, Italy;
0.38-m f/6.8 reflector; position end figures 53s.54, 11".4; image posted at
website URL http://www.astrogeo.va.it/pub/TOCP/PSN_N2554.jpg).

     W. Zheng, P. L. Kelly, I. Shivvers, K. I. Clubb, and A. V. Filippenko,
University of California, Berkeley; and S. B. Cenko, Goddard Space Flight
Center, report that a CCD spectrogram (range 350-1000 nm) of PSN
J08175346+2328105 = SN 2013gq was obtained on Apr. 4.5 UT with the Shane 3-m
reflector (+ Kast spectrograph) at Lick Observatory.  The spectrum shows that
2013gq is an type-Ia supernova.  Cross-correlation with a library of supernova
spectra using the "SuperNova Identification" code (SNID; Blondin and Tonry
2007, Ap.J. 666, 1024) indicates a similarity with several normal type-Ia
supernovae near maximum.  The redshift estimated from SNID is z = 0.014, in
good agreement with the value given in SIMBAD for NGC 2554; adopting this
redshift, the rest-frame photospheric velocity, estimated from the minimum of
the Si II 635.5-nm feature, is about 11400 km/s.

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

                         (C) Copyright 2013 CBAT
2013 November 29                 (CBET 3730)              Daniel W. E. Green