------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 2772 2011 Oct 05 19. 56UT 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 ------------------------------------------------------------------- SUPERNOVA 2011go IN MCG +07-15-2 On 2011 Sept 30 a further possible supernova was reported by Tom Boles, this time in MCG +07-15-2 found during searches for t he UK Nova/Supernova Patrol. It was recorded on Sept 30.146UT at magnitude 18.1 using a 0.35-m Schmidt-Cassegrain telescope and unfiltered CCD. It is located at: RA 06h 55m 51.00s DEC +40o 41' 46.6" (2000), which is approximately 2.3"E and 7.5"N of the nucleus of of MCG +7-15-2 = PGC 19876. The object was designated SN 2011go on CBET 2849. Additional magnitudes: 1989 Nov. 9, [20.5 (Digitised Sky Survey red plate); 1994 Jan. 9, [21.0 (Digitised Sky Survey blue plate); 2010 Dec. 11, [19.5 (Boles); 2011 Mar. 18, [19.5 (Boles); Sept. 30.482, 18.5 (R. A. Koff, Bennett, CO, USA; Meade 0.25-m f/10 Schmidt-Cassegrain reflector + Apogee AP-47p camera; limiting magnitude 19.4; image scale 2"/pixel; position end figures 51s.03, 45".8; UCAC3 re ference stars); 30.581, R = 18.4 (P. Miller, P. Roche, A. Tripp, R. Miles, R. Holmes, S. Foglia, and L. Buzzi; 2.0-m f/10 Faulkes Telescope North + Bessell R filter at Haleakala; position end figures 51s.00, 46".9). S. Valenti and others report t hat a spectrogram obtained on 2011 Oct. 1.01 UT with the Ekar-Copernico 1.82-m telescope (+ AFOSC), shows that is a type-II supernova with strong H_alpha emission showing a broad and narrow component and resemblance to that of SN 2006gy. In a late r report on CBET 2860, J. Vinko, University of Szeged and others report that a spectrogram of Oct. 2.42 UT with the 9.2-m Hobby-Eberly Telescope contains broad P-Cyg Balmer-lines, superimposed on a reddened continuum, plus a strong narrow H-alpha emi ssion peak on top of the broad H-alpha emission component, as reported on CBET 2849. However, inspection of the 2D spectral image reveals that the source of the narrow emission component is the host galaxy, not the supernova. Thus, SN 2011go is pro bably not a super-luminous SN-2006gy-like event having both broad and narrow P-Cyg line profiles, contrary to the previous classification. Features of He I 587.8-nm and O I 777.3-nm are also present in the spectrum. Comparison with supernova temp lates gives early-phase spectra of the normal type-II-P supernovae 1999em and 2006bp as the best resembling templates. It is more likely that SN 2011go is a heavily reddened, but otherwise normal, type-II-P supernova close to maximum light, althoug h a type-IIb classification may also be possible. Congratulations to Tom on the discovery of his 145th supernova. Guy M Hurst