[IAUC] CBET 3753: 20131216 : SUPERNOVA 2013hg = PSN J12095569+2953513

Dom Dic 15 21:22:21 ART 2013

                                                  Electronic Telegram No. 3753
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 2013hg = PSN J12095569+2953513
      Syuichi Nakano, Sumoto, Japan, reports the discovery by Koichi Itagaki
(Teppo-cho, Yamagata) of an apparent supernova (mag 16.9) on an unfiltered CCD
frame (limiting magnitude 18.5) taken remotely on Dec. 10.832 UT using a
0.50-m f/6.8 reflector located at the Takanezawa station, Tochigi-ken.  The
new object is located at R.A. = 12h09m55s.69, Decl. = +29d53'51".3 (equinox
2000.0; reference stars from UCAC3 catalogue), which is 2".1 west and 8".1
south of the nucleus of the presumed host galaxy.  The discovery image was
posted at website URL http://k-itagaki.jp/images/4136.jpg.  The variable was
designated PSN J12095569+2953513 when it was posted at the Central Bureau's
TOCP webpage and is here designated SN 2013hg based on the spectroscopic
confirmation reported below.  Additional CCD magnitudes for 2013hg:  2011
Mar. 31.651, [19.5 (Itagaki); 2013 Nov. 26.793, [18.0 (Itagaki); Dec. 11.122,
V = 16.9 (S. Kiyota, Kamagaya, Japan; remotely with an iTelescope 0.32-m f/8
astrograph + FLI KAF-6303E camera near Nerpio, Spain; image posted at URL
http://meineko.sakura.ne.jp/ccd/PSN_J12095569+2953513.jpg); 11.445, 16.7 (T.
Yusa, Osaki, Japan; remotely using a 0.25-m f/3.4 hyperbolic astrograph + SBIG
ST-10XME camera at the RAS Observatory near Mayhill, NM, U.S.A.; position end
figures 55s.71, 50".9; UCAC4 reference stars; limiting mag 18.5; image posted
at URL http://space.geocities.jp/yusastar77/supernova/PSN_131211.htm); 11.641,
17.0 (Toshihide Noguchi, Katori, Chiba-ken, Japan; 0.23-m f/6.3 reflector +
BITRAN BT-11E camera; eight stacked 30-s exposures; limiting mag 18.5;
position end figures 55s.71, 51".3; UCAC4 reference stars; image posted at
website URL http://park8.wakwak.com/~ngc/images/PSN_N4136.jpg; communicated by
Nakano); 14.178, 16.0 (Massimiliano Martignoni, Magnago, Italy, 0.25-m f/10
Schmidt-Cassegrain reflector; position end figures 55s.70, 50".8; PPMXL
reference stars).

     L. Tomasella, P. Ochner, S. Benetti, A. Pastorello, E. Cappellaro, 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 J12095569+2953513 = SN 2013hg, obtained on Dec.
11.21 UT with the Asiago 1.82-m Copernico Telescope (+ AFOSC), shows it to be
a normal type-Ia supernova.  Assuming that the host galaxy is a dwarf
satellite of nearby NGC 4136, the latter with a recession velocity of 609 km/s
(de Vaucouleurs et al. 1991, RC3.9; via NED), a good match is found with the
type-Ia supernova SN 1994D (Patat et al. 1996, MNRAS 111, 124) about 11 days
before B-band maximum light.  An expansion velocity of about 14000 km/s is
derived from the minimum of the Si II 635.5-nm absorption.  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).

     K. Ayani, Bisei Astronomical Observatory (BAO), Ibara, Okayama, Japan;
and H. Yamaoka, Kyushu University, obtained a low-resolution spectrogram
(range 400-800 nm; resolution 0.6 nm at H-alpha) of PSN J12095569+2953513 = SN
2013hg with the BAO 1.01-m telescope on Dec. 12.8 UT.  The spectrum is that of
a type-Ia supernova around or several days before maximum.  Cross-correlation
with a library of supernova spectra using the "SuperNova Identification" code
(SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that 2013hg matches with
SN 2002he at eight days before maximum.  Assuming that its host galaxy is SDSS
J120955.84+295359.5, whose redshift is 0.0128 (Sloan Digital Sky Survey Data
Release 6; via NED), the blueshift of the Si II 635.5-nm absorption is about
16000 km/s.

     I. Ueno, N. Ebisuda, K. Kawaguchi, K. Takaki, K. Mori, and K. S.
Kawabata, Hiroshima University; and M. Yamanaka, Kyoto University, obtained a
low-resolution optical spectrum (range 500-900 nm) of PSN J12095569+2953513 =
SN 2013hg on Dec. 12.7 UT with the 1.5-m Kanata telescope (+ HOWPol) at the
Higashi-Hiroshima Observatory.  The spectrum is consistent with a pre-maximum
type-Ia supernova.  Assuming that the nearby galaxy, SDSS J120955.84+295359.5
(z = 0.0128, from the Sloan Digital Sky Survey III Data Release 9; via NED),
is the host, the blueshift of the Si II 635.5-nm absorption line corresponds
to -17000 km/s.  A comparison with a library of supernova spectra using GELATO
(Harutyunyan et al. 2008, A.Ap. 488, 383) gives the best match with SN 2002bo
at 12 days before maximum.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2013 CBAT
2013 December 16                 (CBET 3753)              Daniel W. E. Green