Electronic Telegram No. 164
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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CBAT@CFA.HARVARD.EDU (science)
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SUPERNOVA 2005cg
     E. S. Rykoff, University of Michigan, on behalf of the ROTSE
collaboration, reports the discovery of a supernova in unfiltered CCD
images taken on June 2.04 (at mag about 18.2) and 3.03 UT (mag about
17.7) using the 0.45-m ROTSE-IIIc telescope at the 'High-Energy
Stereoscopic Systems' site in Namibia.  SN 2005cg is located at
R.A. = 21h10m50s.42, Decl. = +0o12'07.4" (equinox 2000.0), which is
0".7 north and 0".4 west of the core of the apparent host galaxy.
The new source is not present on ROTSE-IIIc images taken on May
7.14 (limiting mag about 18.4).  R. Quimby, University of Texas, adds
that a spectrum (range 420-890 nm), obtained on June 3.40 with the 9.2-m
Hobby/Eberly Telescope (+ Marcario Low-Resolution Spectrograph) under
very poor conditions by M. Shetrone and S. Rostopchin, shows SN 2005cg
to be a type-Ia supernova.  Taking narrow emission lines at 677 and 501 nm
to be H-alpha and H-beta from the host galaxy gives a redshift of 9290
km/s.  (The host galaxy was observed by the Sloan Digital Sky Survey
at magnitude g' = 19.7; combined with the above redshift, the host
galaxy has an absolute magnitude of -15.9.)


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2005 CBAT
2005 June 4                      (CBET 164)               Daniel W. E. Green