[IAUC] CBET 2691: 20110410 : SUPERNOVA 2011bi IN MCG +07-35-37 = PSN J17100581+4222201

[quai en eps.harvard.edu]

                                                  Electronic Telegram No. 2691
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau en eps.harvard.edu (alternate cbat en iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


SUPERNOVA 2011bi IN MCG +07-35-37 = PSN J17100581+4222201
     T. Boles, Coddenham, England, reports the discovery of an apparent
supernova (mag 17.1) on unfiltered CCD images taken on Apr. 4.041 UT with a
0.35-m reflector.  The new object is located at R.A. = 17h10m05s.81, Decl. =
+42o22'20".1 (equinox 2000.0), which is approximately 7".4 east and 2".1
north of the center of MCG +07-35-37.  Boles also measured position end
figures 05s.83, 20".3 and magnitude V = 17.1 on Apr. 5.116 using a 60-s
unfiltered CCD image (limiting mag 20.5) taken with a 0.61-m Cassegrain
reflector at the Sierra Stars Observatory, Alpine County, California.  Nothing
is present at this position on Boles' images from 2011 Feb. 7 and 2010 Oct. 20
(limiting mag 19.5) or on Digitized Sky Survey plates from 1992 July 21
(limiting red mag 20.5) and 1989 July 2 (limiting blue mag 21.0).  The
variable was designated PSN J17100581+4222201 when posted on the Central
Bureau's TOCP webpage and is here designated SN 2011bi based on the
spectroscopic reports below.

     G. H. Marion, Harvard-Smithsonian Center for Astrophysics (CfA), on
behalf of the CfA Supernova Group, reports that a spectrum (range 340-740 nm)
of PSN J17100581+4222201 = SN 2011bi was obtained on Apr. 4 UT by Marion with
the F. L. Whipple Observatory 1.5-m telescope (+ FAST).  Cross-correlation
with a library of supernova spectra using the "Supernova Identification" code
(SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that 2011bi is a
type-IIP supernova approximately three weeks after the explosion.

     J. Chen, J. Liang, and X. Wang, Tsinghua Center for Astrophysics,
Tsinghua University; and T. Zhang and C. Wu, National Astronomical
Observatories of China (NAOC), report on an optical spectrum (range 400-880
nm) of PSN J17100581+4222201 = SN 2011bi that was obtained on Apr. 8.80 UT
with the 2.16-m telescope (+ OMR) at the Xinglong Station of the NAOC.  The
spectrum is consistent with that of a type-IIP supernova at about one month
after maximum light.  Cross-correlation with a library of supernova spectra
using the "Supernova Identification" code (SNID; Blondin and Tonry 2007,
Ap.J. 666, 1024) shows that 2011bi matches that of SN 2004et at 23 days after
maximum.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2011 CBAT
2011 April 10                    (CBET 2691)              Daniel W. E. Green