SIMBAD references

W. Zheng and M. Hankins, University of Michigan; J. Vinko, University of Szeged; R. Quimby, California Institute of Technology; G. H. Marion, Harvard-Smithsonian Center for Astrophysics; N. Whallon, A. Romadan, B. Sandler, 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 supernova (mag about 17.8) in unfiltered images taken on Aug. 1.41 UT with the 0.45-m ROTSE-IIIb telescope at McDonald Observatory. The new object (designated SN 2011el), which was observed again on Aug. 2.40 UT at mag about 17.6, is located at R.A. = 3:00:18.2, Decl. = +5:49:24.9 (equinox 2000.0; uncertainty about 1"). No apparent host is shown within 2' of this position on the Sloan Digital Sky Survey DR8 frames.

A spectrum, obtained on Aug. 4.45 with the 9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by J. Caldwell, shows that 2011el is a normal type-Ia supernova near maximum. The spectrum contains the Si II 635.5-nm line and several other characteristic type-Ia-supernova features. The Ca II infrared triplet is strong, but no high-velocity component can be identified. The O I 777.3-nm feature is also well developed. According to the SNID software (Blondin and Tonry 2007, Ap.J. 666, 1024), the spectrum most resembles spectra of SN 2002bo at a few days before maximum and SN 1992A at two days after maximum. The median redshift estimate is 0.048. Adopting this redshift, the rest-frame photospheric velocity, estimated from the minimum of the Si II 635.5-nm feature, is about 11000 km/s. The apparent non-detection of the host galaxy down to magnitude r about 23 implies an upper limit of its absolute magnitude of -13.5.

A finding chart for 2011el can be found at the following website URL: http://www.rotse.net/rsvp/j030018.2+054925/ROTSE3_J030018.2+054925.jpg.