[IAUC] CBET 4226: 20151220 : SUPERNOVA 2015bg IN PGC 10563 = PSN J02473451+3454336

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                                                  Electronic Telegram No. 4226
Central Bureau for Astronomical Telegrams
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SUPERNOVA 2015bg IN PGC 10563 = PSN J02473451+3454336
     H. Mikuz, Crni Vrh Observatory, reports the discovery of an apparent
supernova (mag 17.8) by S. Maticic on four unfiltered images taken during Dec.
16.805-16.830 UT with the 60-cm f/3.3 Cichocki telescope at the Crni Vrh
Observatory in the course of the Comet and Asteroid Search Program (PIKA).
The new object is located at R.A. = 2h47m34s.51, Decl. = +34d54'33".6, which
is 13" east and 4" north of the center of the apparent host galaxy.  Nothing
is visible at this position on several Digitized Sky Survey red and blue
images from the Palomar Sky Survey.  An image of the variable was posted at
website URL http://www.observatorij.org/vstars/PSN20151216/PSN20151216.jpg.
The variable was designated PSN J02473451+3454336 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2015bg based on the
spectroscopic confirmation reported below.  Unfiltered CCD exposures taken
remotely by G. Masi using a 43-cm telescope at Ceccano, Italy, on Dec. 17.77
show 2015bg at red mag 18.1 with position end figures 34s.53, 34".1.

     Fang Huang and Han Lin, Tsinghua University; Tianmeng Zhang, National
Astronomical Observatories of China (NAOC); and Xiaofeng Wang, Tsinghua
University, report on an optical spectrum of PSN J02473451+3454336 = SN 2015bg
that was obtained on Dec. 17.6 UT with the 2.16-m telescope (+ OMR) at the
Xinglong Observatory of the NAOC.  The spectrum is consistent with a type-Ia
supernova around maximum light.  Cross-correlation with a library of supernova
spectra using the comparison tool SNID (Blondin and Tonry 2007, Ap.J. 666,
1024) shows that 2015bg matches with SN 2006S at maximum light.  Removing the
redshift of 0.056 for its host galaxy, PGC 10563 (from the SNID fit), they
measure the expansion velocity of the ejecta to be 11000 km/s from the
absorption minimum of Si II 635.5-nm.


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                         (C) Copyright 2015 CBAT
2015 December 20                 (CBET 4226)              Daniel W. E. Green