Electronic Telegram No. 3746
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 2013hb = PSN J01504632+3306356
     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; and E. Christensen and S. M. Larson, Lunar and Planetary
Laboratory, University of Arizona, report the Catalina Real-time Transient
Survey discovery of an apparent supernova in public images from the Catalina
Sky Survey (CSS).

 SN       2013 UT       R.A. (2000.0) Decl.      Mag.
 2013hb   Oct. 7.36    1 50 46.32  +33 06 35.6   17.1

The variable was designated PSN J01504632+3306356 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2013hb based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2013hb:  Sept. 2 UT, [19.7 (CSS); Sept. 17, 18.1 (CSS); Oct. 9.828, 16.3 (N.
James, Chelmsford, Essex, England; Celestron 11 telescope + ST9XE camera;
position end figures 46s.29, 35".6; UCAC-4 reference stars); Oct. 14, 17.4
(CSS); Oct. 23, 18.1 (CSS); Oct. 30, 18.7 (CSS); Nov. 11, 19.3 (CSS); Dec. 2,
19.7.

     L. Tartaglia, P. Ochner, S. Benetti, L. Tomasella, A. Pastorello, N.
Elias-Rosa, E. Cappellaro, and M. Turatto, Istituto Nazionale di Astrofisica,
Osservatorio Astronomico di Padova, report that optical spectroscopy (range
340-820 nm; resolution 1.3 nm), obtained on Dec. 5.84 UT with the Asiago
1.82-m Copernico Telescope (+ AFOSC), shows that PSN J01504632+3306356 = SN
2013hb is likely a type-Ia supernova.  Even after a careful reduction, the
noisy spectrum of the object remains contaminated by the host-galaxy
background.  However, cross-correlation with different libraries of supernovae
spectra gives a good match with a 1991T-like type-Ia supernova at two months
after B-band maximum (adopting a redshift z = 0.035).  They also note that a
fair match can be found with a relatively young (phase around 2 weeks after
maximum) type-Ic supernova at a similar redshift, but this would be in
contrast with the fact that the object was discovered two months earlier.  The
Asiago classification spectra are posted at URL http://graspa.oapd.inaf.it.
The classification was made via GELATO (Harutyunyan et al. 2008, A.Ap. 488,
383) and SNID (Blondin and Tonry 2007, Ap.J. 666, 1024).


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2013 CBAT
2013 December 10                 (CBET 3746)              Daniel W. E. Green