[IAUC] CBET 2896: 20111103 : SUPERNOVA 2011hm IN PGC 7743 = PSN J02021338-0605016

[quai en eps.harvard.edu]

                                                  Electronic Telegram No. 2896
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 2011hm IN PGC 7743 = PSN J02021338-0605016
     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; R. H. McNaught and G. Garradd, Australian National University; 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 public images from the Catalina Sky Survey (CSS).

 SN       2011 UT        R.A. (2000.0) Decl.      Mag.      Offset
 2011hm   Oct. 27.35    2 02 13.38  - 6 05 01.6   18.8    3".2 E, 17".5 S

This variable was designated PSN J02021338-0605016 when it was posted on the
Central Bureau's TOCP webpage and is here designated SN 2011hm based on the
spectroscopic confirmation reported below.  Further CCD magnitudes for 2011hm
(unfiltered unless noted otherwise):  Oct. 17.26 UT, [19.2 (CSS); 30.011, R
= 17.2 (Federica Luppi, Varese, Italy; 0.36-m f/7.9 reflector + Bessell R
filter; position end figures 13s.50, 00".8; reference stars from CMC-14
catalogue); 30.229, 17.8 (Joseph Brimacombe, Cairns, Australia; position end
figures 13s.46, 00".9).  Luppi's image is posted at the following website URL:
http://www.astrogeo.va.it/pub/TOCP/PSN_G-1-6-31.jpg.  Brimacombe's image is
posted at URL http://www.flickr.com/photos/43846774@N02/6297260951/.

     L. Tomasella, S. Valenti, A. Pastorello, M. Fiaschi, and S. Benetti,
Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, on
behalf of a larger collaboration, report that a low-S/N spectrogram of PSN
J02021338-0605016 = SN 2011hm was obtained on Oct. 30.94 UT with the Ekar-
Copernico 1.82-m telescope (+ AFOSC; range 380-820 nm; resolution 2.2 nm).
A comparison of the observed spectrum with a library of supernova spectra
using the "GELATO" code (Harutyunyan et al. 2008, A.Ap. 488, 383) suggests
that 2011hm is a type-II supernova.  A broad H_alpha feature with P-Cyg
profile is visible, along with a number of Fe II features.  From the position
of the minimum of the H_alpha absorption, an expansion velocity of the ejecta
of about 13000 km/s is deduced.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2011 CBAT
2011 November 3                  (CBET 2896)              Daniel W. E. Green