[IAUC] CBET 2881: 20111031 : SUPERNOVA 2011hb = PSN J23275551+0846457

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                                                  Electronic Telegram No. 2881
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 2011hb = PSN J23275551+0846457
     [Editor's note:  This text replaces that on CBET 2877 (offset correction)]
     S. Howerton, Arkansas City, KS, U.S.A.; A. J. Drake, S. G. Djorgovski,
A. Mahabal, M. J. Graham, and R. Williams, California Institute of Technology;
J. L. Prieto, Princeton University; M. Catelan, Pontificia Universidad
Catolica de Chile; R. H. McNaught and G. Garradd, Australian National
University; E. C. Beshore and S. M. Larson, Lunar and Planetary Laboratory,
University of Arizona; and E. Christensen, Gemini Observatory, report the
discovery of an apparent supernova in public images from the Catalina Sky
Survey (CSS).

 SN       2011 UT        R.A. (2000.0) Decl.      Mag.      Offset
 2011hb   Oct. 24.24   23 27 55.51  + 8 46 45.7   18.8    18".0 W, 1".2 N

The variable was designated PSN J23275551+0846457 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2011hb based on
the spectroscopic confirmation reported below.  Additional unfiltered CCD
magnitudes for 2011hb:  Oct. 6.19 UT, [20.5 (CSS); 16.24, 20.3 (CSS); 26.082,
17.3 (L. Elenin, remotely using a 0.45-m f/2.8 astrograph at the ISON-NM
Observatory near Mayhill, NM, USA; limiting mag about 19.7; position end
figures 55.s.55, 45".5; NOMAD reference stars; image posted at website URL
http://spaceobs.org/images/TOCP/PSNJ23275551+0846457.jpg); 26.142, 17.5 (C.
Jacques and E. Pimentel, Belo Horizonte, Brazil; remotely using the GRAS G05
telescope in New Mexico; position end figures 55s.59, 45".2; UCAC2 reference
stars; limiting magnitude 19.0; image posted at the following website URL:
http://ceamig-rea.net/tocp/ngc7674_tocp.jpg).

     G. H. Marion, Harvard-Smithsonian Center for Astrophysics (CfA), on
behalf of the CfA Supernova Group, report that a spectrum (range 340-740 nm)
of PSN J23275551+0846457 = SN 2011hb was obtained on Oct. 28 UT by P. Berlind
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 2011hb is a type-Ia
supernova several days before maximum light.  SNID finds that the best fit is
to a template from the normal type-Ia supernova 2005cf at -10 days.  The Si II
635.5-nm feature is broad and asymmetrical; an estimated redshift of z =
0.028924 for NGC 7674 (Nishiura et al. 2000, A.J. 120, 1691) is used to
measure the velocity at the minimum of this feature to be about 14700 km/s.


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

                         (C) Copyright 2011 CBAT
2011 October 31                  (CBET 2881)              Daniel W. E. Green