SN 2012ek in pgc 62237 - 19 agosto 2012

Stampa

SN 2012ek (A.R. 18 40 28.84, Dec. +36  07 17.4) scoperta il 18 agosto 2012 nella galassia PGC 62237 (offset 13W 12S), magnitudine 18.8, tipo Ib.

SN scoperta da Zhijian Xu, Nanjing, Jiangsu, Xing Gao, Urumqi, Xinjiang (China). Scoperta indipendente di F. Briganti e F. Martinelli con il telescopio SC da 14" dell'Osservatorio di Montecatini Val di Cecina (PI) il 19.896 di agosto.

Electronic Telegram No. 3212
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
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SUPERNOVA 2012ek IN PGC 62237 = PSN J18402884+3607174
    Zhijian Xu, Nanjing, Jiangsu, China; and Xing Gao, Urumqi, Xinjiang,
China, report the discovery of a possible supernova (mag approximately 17.9)
on a 40-s unfiltered CCD image (limiting mag about 18.8) taken by Xing Gao
in the course of the Xingming Sky Survey around Aug. 18.810 UT using a 0.36-m f/6.9 Celestron C14 telescope at Mt. Nanshan. The new object is approximately located at R.A. = 18h40m28s.84, Decl. = +36d07'17".4 (equinox 2000.0; reference stars from USNO-B1.0 catalogue), which is about 13".6 west and 12".2 south of the center of the PGC 62237. Nothing is visible at this position on a red Digitized Sky Survey plate from 1992 Aug. 20 (limiting mag about 19.8). The Xingming images are posted at website URL http://www.xjltp.com/XOSS/XM48ZX/XM48ZX.htm. The object was designated PSN J18402884+3607174 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2012ek based on the spectroscopic confirmation reported below. Additional CCD magnitudes for 2012ek (unfiltered unless noted otherwise): 2012 Aug. 7, [19.0 (Xu and Gao); Aug. 19.64, 17.9 (Xu and Gao; image posted at the following website URL: http://www.flickr.com/photos/75341417@N06/7816496822/in/photostream); Aug. 19.896, 17.8 (Fabio Briganti and Fabio Martinelli, Celestron 14 telescope; independent discovery in the course of survey of the Italian
Supernovae Search Project)
; Aug. 20.206, 18.1 (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 28s.92, 16".6; image posted at http://www.flickr.com/photos/43846774@N02/7824016820/); Aug. 20.62, 17.7 (Xu and Gao). M. Turatto, S. Benetti, A. Pastorello, L. Tomasella, M. Fiaschi, P. Ochner, E. Cappellaro, and S. Valenti, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica, report that a spectrogram of PSN J18402884+3607174 = SN 2012ek, obtained on Aug. 21.79 UT with the Asiago
1.82-m Copernico Telescope (+ AFOSC; range 340-820 nm; resolution 1.4 nm), indicates that it is a type-Ib supernova. Adopting for the host galaxy (PGC 62237) a redshift z = 0.028563 (Freudling et al. 1995, A.Ap. Suppl. 112, 429; via NED), comparison with a library of supernovae spectra via GELATO (Harutyuyan et al. 2008, A.Ap. 488, 383) shows close similarities of the spectrum of 2012ek to spectra of several type-Ib supernovae one week after maximum. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2012 CBAT 2012 August 28 (CBET 3212) Michael Rudenko