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THE ASTRONOMER Electronic Circular No 3004      2014 May 23 14.24UT
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 2014bc IN M106 = PSN J12185771+4718113
Further to TA E-Circular 3003, The Central Bureau advise that this object
has now been designated SN 2014bc.

They also add the offset from the galaxy's nucleus is 3.1 arc seconds
southeast. From images received especially from Nick James it seems very
difficult to separate the object from the galaxy's nuclear region or measure
its brightness reliably.

Additional unfiltered CCD magnitudes:  May 9.98 UT, 17.0: (Giancarlo
Cortini, Italy; 0.35-m f/5.5 Schmidt-Cassegrain reflector + SXVR H-9 camera;
limiting mag 18.5; pre-discovery); 21.830 UT, 14.0 (Cortini); 21.888, 13.5
(Gianluca Masi, et. al. remotely with a 0.43-m telescope near Ceccano,
Italy; position end figures 57s.69, 11".2; low-resolution spectra, obtained
on May 21.90 with a 35.6-cm telescope at Ceccano with a grating having 100
lines/mm and dispersion 3.45 nm/pixel, shows H-alpha emission around 651 nm,
suggesting a type-II supernova; image posted at website URL
http://www.virtualtelescope.eu/?p=8059).

P. Ochner et. al., Osservatorio Astronomico di Padova, Istituto Nazionale di
Astrofisica and G. Terraran, INAF-OAPd and Queen's University, Belfast,
report that a low-S/N optical spectrogram (range 335-785 nm; resolution 0.9
nm), obtained on May 21.82 UT with the Asiago 1.22-m Galileo Telescope (+
Boller & Chivens spectrograph) under the Asiago Transient Classification
Program (Tomasella et al. 2014, as posted at website URL
http://arxiv.org/abs/1403.7233), shows it is an evolved type-II supernova.
The spectrum shows a red continuum having superimposed H-alpha and H-beta
lines with P-Cyg profiles.  From the shallow H-alpha absorption, and
assuming a recession velocity of 448 km/s for the host galaxy, M106 (RC3;
via NED), an expansion velocity of about 3700 km/s is deduced.  A strong Na
I D interstellar absorption suggests the presence of significant extinction.
Superfit (Howell et al. 2005, Ap.J. 634, 1190) gives a good match with SN
1986I at 50 days after discovery. 

Guy M Hurst