Electronic Telegram No. 537
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html


SUPERNOVA 2006ct
     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.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2006 CBAT
2006 June 4                      (CBET 537)               Daniel W. E. Green