Electronic Telegram No. 4211
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
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Prepared using the Tamkin Foundation Computer Network


SUPERNOVA 2015bb IN NGC 5772 = PSN J14513783+4035514
  [Editor's note:  this text replaces that on CBET 4210 (discovery date)]
     Kunihiro Shima, Tokyo, Japan, reports the discovery of an apparent
supernova (mag 17.0) on an unfiltered CCD frame taken on Nov. 16.82 UT with
a 0.45-m f/12 reflector (+ FLI ML-8300 camera) at Fujimi-machi, Nagano,
Japan, in poor weather and at low altitude.  The new object is located at
R.A. = 14h51m37s.83, Decl. = +40d35'51".4 (equinox J2000.0), which is 12"
west and 6" south of the center of NGC 5772.  Nothing is visible at this
position on infrared, red, or blue images from the Digitized Sky Survey.
The variable was designated PSN J14513783+4035514 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2015bb based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2015bb:  Jan. 12.754, [18.2 (Shima); Nov. 18.540, 16.4 (S. Kiyota, Kamagaya,
Japan; remotely with an iTelescope 0.61-m astrograph at the Sierra Remote
Observatory, Auberry, CA, U.S.A.; position end figures 37s.77, 50".6; image
posted at URL http://meineko.sakura.ne.jp/ccd/PSN_J14513783+4035514.jpg);
18.756, V = 16.8, R = 16.4 (Y. Gouda, Hokkaido University, and H. Naito,
Nayoro Observatory; 1.6-m Pirka telescope + MSI at Nayoro Observatory;
reference stars from UCAC-4 catalogue); 19.829, 16.0 (T. Noguchi, Katori,
Chiba-ken, Japan; 0.23-m f/6.3 Schmidt-Cassegrain reflector; position end
figures 37s.89, 51".4; galaxy center position end figures 38s.91, 56".8;
image posted at URL http://park8.wakwak.com/~ngc/images/PSNinNGC5772.jpg;
communicated by S. Nakano, Sumoto, Japan).  SN 2002ee also appeared in NGC
5772 (cf. IAUC 7941).

     T. Nakaoka, R. Itoh, M. Kawabata, Y. Kanda, K. Takata, K. Takaki, and
K. S. Kawabata, Hiroshima University; and M. Yamanaka, Konan University,
obtained low-resolution optical spectrograms (range 450-900 nm) of PSN
J14513783+4035514 = SN 2015bb on Nov. 28.8 and 30.8 UT with the 1.5-m
Kanata telescope (+ HOWPol) at the Higashi-Hiroshima Observatory.  The
spectrum shows absorption of Na I D/He I 587.6-nm, O I 777.4-nm, and a P-Cyg
profile of the Ca II infrared triplet, suggesting that this is a type-Ib/c
supernova.  The absorption component of the Ca II infrared triplet line is
blueshifted by about 8700 km/s.  A comparison with a library of supernova
spectra using GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383) shows that
the spectrum is a good match to the type-Ic supernova 1997X at 1-2 weeks
after B-band maximum.


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

                         (C) Copyright 2015 CBAT
2015 December 4                  (CBET 4211)              Daniel W. E. Green