[IAUC] CBET 2838: 20110929 : SUPERNOVA 2011gf = PSN J21122427-0748521

[quai en eps.harvard.edu]

                                                  Electronic Telegram No. 2838
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 2011gf = PSN J21122427-0748521
     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; 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 unfiltered Catalina Sky Survey images:

 SN       2011 UT        R.A. (2000.0) Decl.      Mag.      Offset
 2011gf   Sep. 18.19   21 12 24.27  - 7 48 52.1   16.6    23".5 E, 21".8 N

This variable was designated PSN J21122427-0748521 when it was posted on the
Central Bureau's TOCP webpage and is here designated SN 2011gf based on the
spectroscopic report below.  Joseph Brimacombe, Cairns, Australia, reports
unfiltered CCD mag 16.1 and position end figures 24s.31, 51".8 from an image
taken on Sept. 19.266 UT; he has posted his image at the following website
URL:  http://www.flickr.com/photos/43846774@N02/6167975455/.

     S. Valenti, S. Benetti, L. Tomasella, and P. Ochner, Osservatorio
Astronomico di Padova, Istituto Nazionale di Astrofisica; and A. Pastorello,
Dipartimento di Astronomia, Universita di Padova, on behalf of a larger
collaboration, report that a spectrogram (range 360-810 nm; resolution 2.2 nm)
of PSN J21122427-0748521 = SN 2011gf, obtained on Sept. 25.90 UT, suggestss
that it is a type-Ia supernova.  Cross-correlation with a library of supernova
spectra via the "GELATO" code (Harutyunyan et al. 2008, A.Ap. 488, 383;
available at URL https://gelato.tng.iac.es/login.cgi), suggest a normal type-Ia
supernova close to the B-band maximum at a redshift of z = 0.0277 (Sloan
Digital Sky Survey, via the NED website).  The expansion velocity deduced from
the Si II 635.5-nm minimum is about 11100 km/s.

     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 J21122427-0748521 = 2011gf was obtained on Sept. 27 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 2011gf is a type-Ia
supernova a few days after maximum light.  The best-fit template spectrum is
that of SN 2007F at +4 days.  The velocity of the Si II 635.5-nm feature is
estimated to be approximately 11600 km/s, using the SNID estimated redshift of
z = 0.027.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2011 CBAT
2011 September 29                (CBET 2838)              Daniel W. E. Green