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THE ASTRONOMER Electronic Circular No 2368      2007 Aug 20 13.37UT
Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise,  Basingstoke,
Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074
INTERNET: GUY@TAHQ.DEMON.CO.UK      Backup: gmh@wdcc1.bnsc.rl.ac.uk
WORLD WIDE WEB                         http://www.theastronomer.org
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SUPERNOVA 2007gr IN NGC 1058
D. Madison and W. Li report the discovery of an apparent supernova in 
NGC 1058 on KAIT images of 2007 Aug. 15.51 (mag 13.8) and 16.47 UT (mag 
13.5).

The new object is located at:
RA 2h 43m 27.98s DEC +37 20' 44.7" (2000), which is 24.8"W and 15.8"N of 
the nucleus of the host galaxy. The new object did not appear on a KAIT 
image of Aug 10.44UT with a limiting magnitude of 18.9 according to CBET 
1034.

R. Chornock et.al., University of California, Berkeley, report that 
inspection of CCD spectra, obtained by D. Reitzel and R. M. Rich 
(University of California, Los Angeles) on Aug. 16.5 UT with the 3-m 
Shane telescope at Lick Observatory, shows it to be a type-Ib/c 
supernova, not long after the explosion.

NGC 1058 was host to two prior supernovae: SN1961V and SN1969L.

Martin Nicholson reports the object is continuing to rise and at V=12.83 
in a message to the BAAVSS on August 19.

According to AAVSO Special Report 59, the two prior SNe in NGC 1058 both 
reached a peak brightness about this level, so SN 2007gr may not get 
much brighter in a note by Arne Henden.

The TA supernova search chart of NGC 1058, last revised on 1990 May 26 
and containing a V sequence to 18.40 based on Asiago Contr. N255 (1971) 
and other sources can be used for the current object. It exists only in 
paper form but can be e-mailed as a scanned item on request.

Guy M Hurst