[IAUC] CBET 3787: 20140118 : SUPERNOVA 2014G IN NGC 3448 = PSN J10543413+5417569

Vie Ene 17 22:47:14 ART 2014

                                                  Electronic Telegram No. 3787
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 2014G IN NGC 3448 = PSN J10543413+5417569
     S. Nakano, Sumoto, Japan, reports the discovery by Koichi Itagaki
(Teppo-cho, Yamagata, Japan) of an apparent supernova (mag 15.6) on an
unfiltered CCD frame (limiting mag 18.5) taken on Jan. 14.574 UT using a
0.50-m f/6.8 reflector remotely at the Takanezawa station, Tochigi-ken.  The
new object is located at R.A. = 10h54m34s.13, Decl. = +54d17'56".9 (equinox
2000.0), which is 44" west and 20" south of the center of NGC 3448.  The
discovery image was posted at URL http://www.k-itagaki.jp/images/3448.jpg.
The variable was designated PSN J10543413+5417569 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2014G based on the
spectroscopic confirmation reported below.  Patrick Wiggins (observing near
Erda, UT, USA, with a Celestron C14 reflector + SBIG ST-10XME camera) reports
an independent discovery of this variable at mag about 17 with position end
figures 34s.19, 56".8 from images apparently taken on Jan. 14.317 and 14.542,
adding that nothing was visible at this position on an image taken on Jan. 6
(no limiting-magnitude information provided); his image posted at website URL
http://users.wirelessbeehive.com/~paw/temp/NGC3448_2014JAN06-14.JPG).
     Additional CCD magnitudes for 2014G:  Jan. 6.633, [18.5 (Itagaki); 10.85,
[19.4 (D. Denisenko, V. Lipunov, and E. Gorbovskoy; 0.40-m f/2.5 MASTER-Amur
reflector; six co-added 60-s exposures); 13.611, 17.5 (Itagaki; pre-discovery
image; out-of-focus); 14.496, 15.6 (Hidetaka Sato, Tokyo, Japan; remotely with
an iTelescope T21 CDK f/4.5 reflector + PL-6303E camera; communicated by
Nakano); 14.523, R = 15.5 (P. Lake; 0.25-m f/3.4 astrograph near Mayhill, NM,
USA); 15.111, V = 15.26 and I_c = 15.06 (Seiichiro Kiyota, Kamagaya, Chiba,
Japan; remotely with an iTelescope 0.5-m astrograph + FLI ProLine PL11002M
camera near Mayhill); 15.309, V = 15.2, R = 15.0, I_c = 14.7 (T. Yusa, Osaki,
Japan; remotely using an iTelescope 0.50-m f/6.8 astrograph near Mayhill;
position end figures 34s.14, 56".3; limiting magnitude 18.0); 15.461, R = 14.5
(Lake; 0.51-m f/4.5 astrograph near Mayhill); 15.576, 15.1 (Toshihide Noguchi,
Katori, Chiba-ken, Japan; 0.23-m f/6.3 Schmidt-Cassegrain reflector + BITRAN
BT-11E; position end figures 34s.13, 56".2; offset 46" west, 23" south;
limiting mag 17.5; reference stars from UCAC4 catalogue; image posted at
website URL http://park8.wakwak.com/~ngc/images/PSNinNGC3448.jpg; communicated
by Nakano); 15.67, 15.2 (K. Kadota, Ageo, Japan; 0.25-m reflector; position
end figures 34s.12, 56".3; limiting mag 18.4; image posted at website URL
http://members.jcom.home.ne.jp/kenic-k/image/PSNinNGC3448-20140115.jpg;
communicated by Nakano).

     R. Itoh, Y. Moritani, and K. S. Kawabata, Hiroshima University; and M.
Yamanaka, Kyoto University, obtained a low-resolution optical spectrum (range
480-900 nm) of PSN J10543413+5417569 = SN 2014G on Jan. 14.6 UT with the 1.5-m
Kanata telescope (+ HOWPol) at Higashi-Hiroshima Observatory.  The spectrum
shows a blue continuum and a broad P-Cyg profile of H-alpha, suggesting that
this is an early type-II supernova.  A comparison with a library of supernova
spectra using GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383) reveals that
the spectrum gives a good match to those of several type-II supernovae (e.g.,
SNe 2006bp and 2009au) close to maximum light.

     P. Ochner, A. Siviero, L. Tomasella, S. Benetti, E. Cappellaro, N.
Elias-Rosa, A. Pastorello, L. Tartaglia, G. Terreran, and M. Turatto,
Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica, report
that an optical spectrogram (range 360-790 nm; resolution 0.8 nm) of PSN
J10543413+5417569 = SN 2014G, obtained on Jan. 15.13 UT with the Asiago 1.22-m
Galileo Telescope (+ Boller & Chivens spectrograph), shows that it is a
type-IIn supernova soon after the explosion.  A very good match is found with
the spectrum of the type-IIn supernova 2013cj.  The spectrum of 2014G is
dominated by hydrogen Balmer lines emission, consisting of unresolved narrow
components (FWHM < 550 km/s, as measured for H_alpha) on broader wings (FWHM
about 3400 km/s again for H_alpha).  An unusually strong He II 468.6-nm
feature is also visible, together with weaker He I lines.  Given the redshift
of the parent galaxy, NGC 3448 (z about 0.004503, after de Vaucouleurs et al.
1991, RC3.9; via NED), and the magnitude at discovery, the derived absolute
magnitude for this event is about -15.8.  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
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                         (C) Copyright 2014 CBAT
2014 January 18                  (CBET 3787)              Daniel W. E. Green