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THE ASTRONOMER Electronic Circular No 2729      2011 Apr 07 14.21UT
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 2011bc IN NGC 4076 = PSN J12043294+2012114
Further to the preliminary announcement on TA E-Circular 2728, this 
object has been confirmed spectroscopically and designated supernova 
2011bc. The type-Ia supernova 2007M also appeared in NGC 4076 (cf. CBET 
816).

G. H. Marion, Harvard-Smithsonian Center for Astrophysics (CfA), on 
behalf of the CfA Supernova Group, reports on CBET 2684 that a spectrum 
was obtained on 2011 Apr. 3 UT by Marion with the F. L. Whipple 
Observatory 1.5-m telescope. Cross-correlation with a library of 
supernova spectra using the "Supernova Identification" code shows that 
the object is a type-Ia supernova several days before maximum light. 
Using the NED redshift of z = 0.020728 for NGC 4076 (which is the 
presumed host), they estimate the velocity of the Si II 635.5-nm feature 
to be approximately 17000 km/s.

David Balam, Dominion Astrophysical Observatory, National Research 
Council of Canada (NRCC) et. al., report that a spectrogram (range 
361-670 nm, resolution 0.3 nm) obtained on Apr. 7.34 UT with the 1.82-m 
Plaskett Telescope of the NRCC, shows it to be a type-Ia supernova 
before maximum light.  Cross-correlation with a library of supernova 
spectra using the "Supernova Identification" code
indicates that 2011bc is most similar to the type-Ia supernova 1999ee at 
one week before maximum light.

Congratulations to Ron Arbour on this confirmation of his supernova 
discovery, his 25th.

Guy M Hurst