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@eps.harvard.edu (alternate cbat@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 superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2013 CBAT 2013 December 16 (CBET 3753) Daniel W. E. Green