Electronic Telegram No. 2719
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@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


SUPERNOVA 2011ci = PSN J10180041-0232414
     A. J. Drake, S. G. Djorgovski, A. Mahabal, M. J. Graham, and R. Williams,
California Institute of Technology; J. L. Prieto, Carnegie Observatories;
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 Catalina Real-time Transient
Survey's discovery of an apparent supernova in unfiltered Catalina Sky Survey
images:

 SN       2011 UT        R.A. (2000.0) Decl.      Mag.      Offset
 2011ci   May  4.16    10 18 00.41  - 2 32 41.4   17.6       1" N

This variable was designated PSN J10180041-0232414 when posted at the Central
Bureau's TOCP webpage and is here designated SN 2011ci based on the
spectroscopic report below.
     R. A. Koff (Bennett, CO, U.S.A.) reports magnitude 17.6 and position end
figures 00s.41, 41".5 from co-added images taken on May 5.172 UT.  Joseph
Brimacombe, Coral Towers Observatory, Cairns, Australia, writes that red-
filtered images taken with a 30-cm reflector on May 7.508 UT show 2011ci at
magnitude R = 17.5 (position end figures 00s.45, 42".3); his image is posted
at website URL http://www.flickr.com/photos/43846774@N02/5699601130/.

     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
J10180041-0232414 = 2011ci was obtained on May 5 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 2011ci is a type-Ia
supernova a few days before maximum light.  The velocity of the Si II 635.5-nm
feature is estimated to be approximately 11300 km/s, using an estimated
redshift of z = 0.0511, measured from host-galaxy emission lines.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2011 CBAT
2011 May 11                      (CBET 2719)              Daniel W. E. Green