[IAUC] CBET 3035: 20120227 : SUPERNOVA 2012an IN NGC 6373 = PSN J17241023+5900069

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                                                  Electronic Telegram No. 3035
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 2012an IN NGC 6373 = PSN J17241023+5900069
     J. Newton and T. Puckett report the discovery of an apparent supernova
(mag 17.4) on an unfiltered CCD image (limiting mag 19.1) taken with a 0.40-m
reflector at Portal, AZ, U.S.A., on Feb. 21.5291 UT in the course of the
Puckett Observatory Supernova Search.  The new object, which was confirmed
at mag 17.4 on Feb. 22.543 by Puckett with the 40-cm reflector at Portal, is
located at R.A. = 17h24m10s.23, Decl. = +59o00'06".9 (equinox 2000.0), which
is 16".3 east and 24".2 north of the center of NGC 6373.  Nothing is visible
at this position on images taken by Puckett on 2011 Mar. 21 (limiting mag
19.2).  The variable was designated PSN J17241023+5900069 when it was posted
at the Central Bureau's TOCP webpage and is here designated SN 2012an based
on the spectroscopic confirmation reported below.  The discoverers posted an
image of 2012an at URL http://www.possdata.com/PSNJ17241023+5900069.jpg.
Additional CCD magnitudes for 2012an (unfiltered unless noted otherwise):
Feb. 22.191, 17.0 (F. Luppi and L. Buzzi, Varese, Italy; 0.38-m reflector;
position end figures 10s.28, 06".5; reference stars from the NOMAD catalogue;
image posted at website URL http://www.astrogeo.va.it/pub/TOCP/PSN_N6373.jpg);
22.501, 17.1 (L. Elenin, Lyubertsy, Russia; and I. Molotov, Moscow, Russia;
remotely with a 0.45-m f/2.8 telescope at the ISON-NM Observatory near Mayhill,
NM, USA; position end figures 10s.26, 06".2; NOMAD reference stars; limiting
mag about 20.2); 22.516, 17.6 (J. Brimacombe, Cairns, Australia; remotely using
a 51-cm RCOS telescope + STL11K camera + luminance filter at the New Mexico
Skies Observatory near Mayhill, NM, U.S.A.; position end figures 10s.32, 06".1;
image posted at URL http://www.flickr.com/photos/43846774@N02/6775323836/).
The type-II supernova 2001ad also appeared in NGC 6373 (cf. IAUCs 7596, 7597).

     S. W. Jha, C. McCully, and B. Patel, Rutgers University, report that a
spectrum (range 460-980 nm) of SN 2012an = PSN J17241023+5900069, taken on
Feb. 26.7 UT with the Keck II 10-m telescope (+ DEIMOS), shows it to be a
type-IIb supernova, likely one to two weeks after explosion.  The spectrum
shows strong P-Cyg profiles of H-alpha and He I 587.6-, 667.8-, and 706.5-nm.
Adopting a recession velocity for NGC 6373 of 3320 km/s (Falco et al. 1999,
PASP 111, 438) yields an expansion velocity of 12900 km/s (from the H-alpha
minimum) or 9000 km/s (from the minima of the He I features).  Cross-
correlation with a library of supernova spectra using the "Supernova
Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) yields a
good match to the type-IIb supernova 1997dd, though with an uncertain age.


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

                         (C) Copyright 2012 CBAT
2012 February 27                 (CBET 3035)              Daniel W. E. Green