SIMBAD references

W. Zheng, University of Michigan; J. Vinko, University of Szeged; R. Quimby, California Institute of Technology; A. Romadan, N. Whallon, B. Sandler, S. B. Pandey, F. Yuan, and C. Akerlof, University of Michigan; and J. C. Wheeler and E. Chatzopoulos, University of Texas, on behalf of the ROTSE collaboration, report the discovery of a new supernova (mag about 19.0) in unfiltered images taken on Feb. 11.21 UT with the 0.45-m ROTSE-IIIb telescope at McDonald Observatory. The new object, which was observed again on Feb. 12.25 at mag about 18.6, is located at R.A. = 11:45:59.58, Decl. = +46:46:50.5 (equinox 2000.0; uncertainty about 1"), which is 1".0 west and 1".0 south of the center of the presumed host galaxy (SDSS J114559.68+464651.5). A finding chart for 2011ad can be found at the following website URL: http://www.rotse.net/rsvp/j114559.6+464651/j114559.6+464651.jpg. A spectrum, obtained on Feb. 15.24 with the 9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by S. Rostopchin, shows that 2011ad is a type-Ia supernova near maximum light. The spectrum contains the Si II 635.5-nm line and several other characteristic type-Ia-supernova features. According to SNID (Blondin and Tonry 2007, Ap.J. 666, 1024), the spectrum of 2011ad most resembles those of SN 1995D (at 4.2 days after maximum) and SN 2002er (at 6.4 days before maximum). The median redshift estimate is z = 0.092. Adopting this redshift, the velocity (from the absorption minimum of the Si II 635.5-nm feature) is 11200 km/s.