2010CBET.2523....1Z

W. Zheng, University of Michigan; J. Vinko, University of Szeged; R. Quimby, California Institute of Technology; N. Whallon, A. Romadan, Y. Chen, C. Akerlof, S. B. Pandey, and F. Yuan, University of Michigan; and J. C. Wheeler and E. Chatzopoulos, University of Texas, on behalf of the ROTSE collaboration, report the discovery of an apparent supernova (first announced at website URL http://www.astronomerstelegram.org/?read=2936) of mag about 17.4 in unfiltered images taken on Sept. 20.99 UT with the 0.45-m ROTSE-IIIc telescope at the H.E.S.S. site in Namibia. The new object is located at R.A. = 3:37:22.20, Decl. = -33:02:39.7 (equinox 2000.0; uncertainty about 1"), which is 5".1 west and 4".5 south of the center of the presumed host galaxy 2MASX J03372260-3302350 (which hosted the type-Ia supernova 1990Y; cf. IAUC 5083). No source was detected at this position in ROTSE-IIIc images taken on Sept. 9 and earlier (limiting mag 19.5). Additional approximate ROTSE magnitudes for 2010jd: Sept. 21.99, 17.4; Oct. 2.06, 17.3; 11.02, 17.6; 13.02, 17.7.