Supernova 2013bi in NGC 6632 = Psn J18250198+2731537 = Psn J18250195+2731541
Abstract
Zhangwei Jin, Ningbo, Zhejiang, China; and Xing Gao, Urumqi, Xinjiang, China, report the discovery of an apparent supernova (mag approximately 16.4) on an unfiltered 40-s survey CCD image (limiting mag about 19.5) taken by Xing Gao in the course of the Xingming Sky Survey around Mar. 24.9134 UT using a Celestron C14 telescope at Mt. Nanshan. The new object is approximately located at R.A. = 18h25m01s.98, Decl. = +27d31'53".7 (equinox 2000.0), which is about 12".6 west and 13".3 south of the center of NGC 6632. The Xingming images have been posted at URL http://www.xjltp.com/XOSS/XM44ZJ/XM44ZJ.htm. The variable was designated PSN J18250198+2731537 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2013bi based on the spectroscopic confirmation reported below; a later independent discovery posting to the TOCP by T. Puckett yielded a second preliminary designation (PSN J18250195+2731541). Additional magnitudes for 2013bi (via unfiltered CCD unless noted otherwise): 1989 May 3, [19.8 (red Digitized Sky Survey plate; via Jin and Gao); 2013 Mar. 20, [19.2 (Xingming archival images); 25.462, 15.7 (L. Elenin, Lyubertsy, Russia; and I. Molotov, Moscow; three 300-s images remotely taken with a 0.45-m f/2.8 telescope at the ISON-NM Observatory near Mayhill, NM, USA; limiting mag about 19.7; position end figures 02s.00 +/- 0".11, 54".0 +/- 0".1; UCAC-4 reference stars; image posted at http://spaceobs.org/images/TOCP/PSNJ18250198+2731537-20130325.png); 25.436, 15.6 (Joseph Brimacombe, Cairns, Australia; remotely with a 51-cm RCOS telescope + infrared filter located at the New Mexico Skies observatory near Mayhill; bandpass > 700 nm; position end figures 01s.98, 54".0; image posted at website URL http://www.flickr.com/photos/43846774@N02/8594682460/); Apr. 3.98, 16.0 (Gianluca Masi; remotely with the 43-cm Virtual Telescope robotic facility in Italy); 9.914, 16.4 (Jin and Gao; position end figures 01s.96, 54".0); 11.469, 16.0 (Puckett; position end figures 01s.95, 54".1; offset 14".5 west, 12".7 south). D. Milisavljevic, E. Berger, and A. Soderberg, Harvard-Smithsonian Center for Astrophysics; and E. O. Martin, MMT Observatory, report that a low-dispersion spectrogram (range 335-855 nm), obtained on Apr. 14.5 UT with the 6.5-m MMT reflector (+ Blue Channel), shows PSN J18250198+2731537 = SN 2013bi to be a type-II supernova. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows good matches with the type-IIP event 2004et at approximately 2-4 weeks after maximum light. Using a redshift of z = 0.016 for the host galaxy (NGC 6632) as measured from narrow nebular emission lines, they estimate the minimum of the H_alpha P-Cyg absorption to be blueshifted by approximately -9400 km/s.
- Publication:
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Central Bureau Electronic Telegrams
- Pub Date:
- April 2013
- Bibcode:
- 2013CBET.3481....1J