2006CBET..537....1Q

Further to IAUC 8622, R. Quimby and P. Mondol, University of Texas, report the discovery of an apparent supernova in unfiltered CCD images taken on May 25.21 (at mag about 17.0), 31.21 (mag about 16.9), and June 3.19 UT (mag about 16.6) using the 0.45-m ROTSE-IIIb telescope at the McDonald Observatory. SN 2006ct is located at R.A. = 12h09m57s.03, Decl= +47o05'43".9 (equinox 2000.0), which is 3".4 east and 1".4 south of the center of the apparent host galaxy. SN 2006ct was found by subtracting a co-addition of images taken between 2004 Dec. 15 and 2006 Jan. 28 (limiting mag about 18.7) from the 2006 May images. A spectrum (range 420-890 nm) of 2006ct, obtained on June 4.19 with the 9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by S. C. Odewahn and S. Rostopchin, shows it to be a type-Ia supernova. The seeing was poor during the observations, and light from the apparent host galaxy contaminates the spectrum. Subtracting off the estimated host contribution using Sloan Digital Sky Survey spectra taken prior to the supernova, the spectrum is similar to that of SN 1992A near maximum light (Filippenko et al. 1992, A.J. 104, 1543), but with much slower line velocities. Using the SDSS catalogued redshift for the host (z = 0.0315), the minimum of the Si II 635.5-nm feature is blue-shifted by 6000 km/s.