[IAUC] CBET 2784: 20110809 : SUPERNOVA 2011el

[quai en eps.harvard.edu]

                                                  Electronic Telegram No. 2784
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 2011el
     W. Zheng and M. Hankins, University of Michigan; J. Vinko, University of
Szeged; R. Quimby, California Institute of Technology; G. H. Marion,
Harvard-Smithsonian Center for Astrophysics; N. Whallon, A. Romadan, B.
Sandler, F. Yuan, and C. Akerlof, University of Michigan; and J. C. Wheeler
and E. Chatzopoulos, University of Texas, on behalf of the ROTSE collaboration,
report the discovery of a supernova (mag about 17.8) in unfiltered images
taken on Aug. 1.41 UT with the 0.45-m ROTSE-IIIb telescope at McDonald
Observatory.  The new object (designated SN 2011el), which was observed again
on Aug. 2.40 UT at mag about 17.6, is located at R.A. = 3h00m18s.2, Decl. =
+5d49'24".9 (equinox 2000.0; uncertainty about 1").  No apparent host is shown
within 2' of this position on the Sloan Digital Sky Survey DR8 frames.
     A spectrum, obtained on Aug. 4.45 with the 9.2-m Hobby-Eberly Telescope
(+ Marcario Low-Resolution Spectrograph) by J. Caldwell, shows that 2011el
is a normal type-Ia supernova near maximum.  The spectrum contains the Si II
635.5-nm line and several other characteristic type-Ia-supernova features.
The Ca II infrared triplet is strong, but no high-velocity component can be
identified.  The O I 777.3-nm feature is also well developed.  According to
the SNID software (Blondin and Tonry 2007, Ap.J. 666, 1024), the spectrum
most resembles spectra of SN 2002bo at a few days before maximum and SN
1992A at two days after maximum.  The median redshift estimate is 0.048.
Adopting this redshift, the rest-frame photospheric velocity, estimated from
the minimum of the Si II 635.5-nm feature, is about 11000 km/s.  The apparent
non-detection of the host galaxy down to magnitude r about 23 implies an
upper limit of its absolute magnitude of -13.5.
     A finding chart for 2011el can be found at the following website URL:
http://www.rotse.net/rsvp/j030018.2+054925/ROTSE3_J030018.2+054925.jpg.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2011 CBAT
2011 August 9                    (CBET 2784)              Daniel W. E. Green