Electronic Telegram No. 3836
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 2013hx
     R. Scalzo, F. Yuan, M. Childress, and B. Schmidt, Australian National
University (ANU); and B. Tucker, ANU and University of California at Berkeley,
report the discovery of an apparent supernova (at magnitudes g = 17.6 and r =
17.9) in g-band and r-band images obtained with the SkyMapper telescope
(Keller et al. 2007, Publ. Astron. Soc. Australia 24, 1) at Siding Spring on
2013 Dec. 31.55 UT.  The new object is located at R.A. = 1h35m33s.28, Decl. =
-57d57'50".6 (equinox 2000.0).  Pre-discovery images from 2013 Dec. 11 show
nothing at this position to limiting magnitude g = 19.5 (95-percent
confidence).  The variable (designated SN 2013hx based on the spectroscopic
report below) steadily rose in luminosity to achieve a peak brightness of g =
16.9 and r = 17.0 on 2014 Jan. 26, declining slowly to r = 17.5 on Feb. 24
before it was lost in the western sky.  There is no visible host galaxy down
to magnitude g = 19.5 visible on a pre-discovery image from SkyMapper.

     C. Inserra, S. J. Smartt, and M. Nicholl, Queen's University, Belfast;
M. Fraser, Heather Campbell, Nadia Blagorodnova, and Nic Walton, Institute of
Astronomy; Nancy Elias-Rosa, Osservatorio Astronomico di Padova, Istituto
Nazionale di Astrofisica (INAF); Annalisa De Cia, Weizmann Institute for
Science; M. Childress, R. Scalzo, F. Yuan, and B. Schmidt, Australian National
University (ANU); B. Tucker, ANU and University of California, Berkeley; S.
Benetti and A. Pastorello, Osservatorio Astronomico di Padova, INAF; K.
Smith and D. Young, Queen's University, Belfast; M. Sullivan, University of
Southampton; S. Taubenberger, Max-Planck-Institut fuer Astrophysik, Garching;
S. Valenti, Las Cumbres Observatory Global Telescope; O. Yaron and A. Gal-Yam,
Weizmann Institute for Science; and C. Knapic, R. Smareglia, and M. Molinaro,
Trieste Astronomical Observatory, INAF, report that they obtained a
spectrogram of SN 2013hx on 2014 Feb. 20 UT with the European Southern
Observatory's New Technology Telescope at La Silla, using EFOSC2 with Grism 13
(range 398.5-931.5 nm; 1.8-nm resolution).  They identified a narrow emission
feature at 750.0 nm that is consistent with H_alpha at redshift z = 0.135.
The object shows broad features in the blue that are consistent with those
seen in super-luminous type-Ic supernovae (Inserra et al. 2013, Ap.J. 770,
128) with the addition of Balmer lines such as H_beta and H_gamma.  Thus,
taking in account both the spectral features and the peak brightness, they
conclude that 2013hx is a super-luminous type-Ic supernova.


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

                         (C) Copyright 2014 CBAT
2014 March 22                    (CBET 3836)              Daniel W. E. Green