Electronic Telegram No. 3338 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 2012ho IN MCG -01-57-21 = PSN J22401702-0225341 Koichi Itagaki, Yamagata, Japan, reports his discovery of an apparent supernova (mag 15.6) on an unfiltered CCD image (limiting magnitude 18.5) taken on Dec. 6.383 UT with a 0.3-m f/7.8 reflector. The new object is located at R.A. = 22h40m17s.02, Decl. = -2d25'34".1 (equinox 2000.0; UCAC3 reference stars), which is 27" east and 6" south of the center of MCG -01-57-21 = PGC 69448. The discovery image is posted at the following website URL: http://www.k-itagaki.jp/psn.jpg. The variable was designated PSN J22401702-0225341 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2012ho based on the spectroscopic confirmation reported below. Additional unfiltered CCD magnitudes for 2012ho: Nov. 9.402, [19.0 (Itagaki); Dec. 6.441, 15.7 (Toshihide Noguchi, Katori, Chiba-ken, Japan; 0.23-m f/6.3 Schmidt-Cassegrain reflector; limiting mag 18.0; position end figures 17s.03, 34".1; presumed host galaxy center has position end figures 15s.09, 27".6; communicated by S. Nakano, Sumoto, Japan; image posted at website URL http://park8.wakwak.com/~ngc/images/PSN_J22401702-0225341.jpg); 6.454, 15.3 (T. Yusa and N. Wada, Osaki, Japan; 0.3-m f/9.9 Cassegrain reflector + SBIG STL-1001E camera; position end figures 17s.05, 34".1; UCAC-3 reference stars; limiting mag 18.5); 8.069, 15.4 (L. Elenin, Lyubertsy, Russia; and I. Molotov, Moscow; remotely taken at with a 0.45-m f/2.8 telescope at the ISON-NM Observatory near Mayhill, NM, USA; limiting mag about 20.5; position end figures 17s.04 +/- 0".09, 34".3 +/- 0".05; UCAC-4 reference stars; image posted at http://spaceobs.org/images/TOCP/PSNJ22401702-0225341-20121208.png); 8.099, 15.2 (Joseph Brimacombe, Cairns, Australia; remotely with a 51-cm RCOS telescope + luminance filter at the New Mexico Skies Observaotry near Mayhill; position end figures 17s.03, 34".0). Yusa's image is posted at website URL http://space.geocities.jp/yusastar77/supernova/PSNi121206.htm; Brimacombe's image is posted at http://www.flickr.com/photos/43846774@N02/8261896229/. K. Takaki, R. Itoh, K. Kawaguchi, K. S. Kawabata, I. Ueno, Y. Moritani, H. Akitaya, and T. Urano, Hiroshima University; and M. Yamanaka, Kyoto University, obtained a low-resolution optical spectrum (range 480-900 nm) of PSN J22401702-0225341 = SN 2012ho on Dec. 6.53 UT with the 1.5-m Kanata telescope (+ HOWPol) at Higashi-Hiroshima Observatory. The spectrum is dominated by blue continuum emission, and no significant spectral feature is seen, which is consistent with a type-II supernova around maximum. A comparison with a library of supernova spectra using GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383) suggests that the spectrum is a good match for various type-II supernovae where blue continuum dominates, such as the type-IIP supernova 1999gi at -3 days, the type-IIn supernova 1998S (IIn) at +1 day, and the luminous type-IIL supernova 2008es at +3 days. J.-J. Zhang, Yunnan Astronimical Observatory (YNAO); X.-L. Zhao and X.-F. Wang, Tsinghua Center for Astrophysics, Tsinghua University; and L.-F. Wang, Texas A&M University, report on an optical spectrogram (range 320-870 nm) of PSN J22401702-0225341 = SN 2012ho that was obtained on Dec. 7.50 UT with the 2.4-m telescope (+ YFOSC) at the LiJiang Gaomeigu Station of the YNAO. The spectrum is very blue and relatively featureless, with broad, low-contrast hydrogen Balmer emission lines. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that 2012ho matches with the type-II supernova 1999em at -4 days. Adopting a recession velocity 2970 km/s for the presumed host galaxy (Theureau et al. 1998, A.Ap. Suppl. 130, 333), the photospheric expansion velocities, inferred from the absorption minima of H_alpha and H_gamma, are about 13000 km/s. Follow-up observations are encouraged. J. M. Silverman, University of Texas; J. Vinko, University of Szeged; R. Quimby, Kavli IPMU, University of Tokyo; J. C. Wheeler and E. Chatzopoulos, University of Texas; J. T. Parrent, Dartmouth College, and Las Cumbres Observatory Global Telescope; and G. H. Marion and D. Milisavljevic, Harvard-Smithsonian Center for Astrophysics, report that inspection of a spectrogram, obtained on Dec. 7.05 UT with the 9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by S. Rostopchin, shows that PSN J22401702-0225341 = SN 2012ho is a young type-II supernova. The very blue continuum shows weak, somewhat-broad P-Cyg Balmer and He I features. After removal of the host-galaxy recession velocity of 2970 km/s (from narrow emission lines), the absorption minimum of the H-alpha line is found to be blueshifted by about 15200 km/s. Cross-correlation with a library of supernova spectra using the "SuperNova IDentification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2012ho is a type-IIP supernova a few days after explosion. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2012 CBAT 2012 December 12 (CBET 3338) Daniel W. E. Green