2009CBET.2056....1Z

W. Zheng, F. Yuan, University of Michigan; J. Vinko, University of Szeged; R. Quimby, California Institute of Technology; D. Chamarro, M. D. Sisson, N. Whallon, C. Akerlof, and S. B. Pandey, University of Michigan; and J. C. Wheeler and E. Chatzopoulos, University of Texas, on behalf of the ROTSE collaboration, report the discovery of a type-Ia supernova (mag about 19.0) in unfiltered images taken on Nov. 6.87 UT with the 0.45-m ROTSE-IIIc telescope at the H.E.S.S. site in Namibia. The new object, which was observed again a week later at mag about 18.4, is located at R.A. = 0:41:12.70, Decl. = -9:08:53.0 (equinox 2000.0; uncertainty about 1"), which is 3".2 west and 7".2 north of the center of the galaxy SDSS J004112.90-090900.4, at a redshift of z = 0.053 (according to the Sloan Digital Sky Survey database). A finding chart for the object can be found at http://www.rotse.net/rsvp/j004112.7-090853/j004112.7-090853.jpg. An HET/LRS spectrum obtained by S. C. Odewahn on Nov. 23.13 UT shows 2009ly to be a type-Ia supernova, 2-3 weeks after maximum light. According to SNID, the spectrum best resembles those of SN 1981B (24 days after maximum) and SN 1994D (+14 days) at redshift z = 0.053, the same as the host galaxy from SDSS. The Si II 635.5-nm line appears to be slightly blended with Fe II. The photospheric velocity, estimated from the minimum of the Si II 635.5-nm feature, and corrected for the host-galaxy redshift, is about 10000 km/s.