Electronic Telegram No. 666
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html


POSSIBLE SUPERNOVA IN UGC 4904
     S. Nakano, Sumoto, Japan, reports the discovery of a possible supernova
(mag 13.8) by K. Itagaki (Teppo-cho, Yamagata, Japan) on numerous unfiltered
CCD frames taken around 2006 Oct. 9.752 UT using a 0.60-m f/5.7 reflector.
Itagaki provides a position for this object as follows:  R.A. = 9h17m20s.78,
Decl. = +41o54'32".7 (equinox 2000.0), which is 11" west and 7" south of the
center of UGC 4904.  An independent discovery of this object, also at mag
13.8, has been reported by T. Puckett and R. Gorelli from an unfiltered CCD
image taken with a 0.35-m reflector at Ellijay, GA, on 2006 Oct. 10.33 in
the course of the Puckett Observatory Supernova Search, the position end
figures given as 20s.85, 33".0 (and offset 8".8 west, 8".8 south of the
galaxy center).  Additional recent magnitudes for the variable object:  2005
Dec. 11, [19.8 (Puckett); 2006 Sept. 21.793, [19.5 (Itagaki); 22, [19.0
(Itagaki); Oct. 10.725, 13.9 (Itagaki).  Itagaki adds that nothing is
visible at this location on the Digitized Sky Survey (DSS).
     As a potentially significant aside, Itagaki had reported (via H.
Yamaoka, Kyushu University, on 2004 Oct. 20) a possible supernova close to
the above position, and near the limit of his CCD frames, having position
end figures 20s.81, 32".3.  The following approximate magnitudes were then
provided by Itagaki for that object, all 2004 dates:  Oct. 1, [19.0; Sept.
18, [19.0; Oct. 15.816, 19.0 (near limit); 17.820, 19.0 (discovery).  Now,
Nakano reports the following apparently revised magnitudes from Itagaki
from his 2004 frames:  Oct. 14.816, 17.9; 15.806, 18.2; 16.819, 18.2;
21.794, 18.4; 23.772, 18.5; 23.775, 18.7; Nov. 7.713, [19.5; 9.757, [19.0;
22.675, [19.0.  The average position end figures for the object from these
same 2004 frames from Itagaki are 20s.82 +/- 0s.02, 32".6 +/- 0.4.  In
2004, Yamaoka reported that he had examined Itagaki's images and the DSS
images:  The DSS blue images taken on 1953 Apr. 15, 1990 Jan. 29, and 1995
Nov. 23 show a starlike object of mag about 20 near (within 2" of) the
reported position, noting that this had also been noticed by Itagaki, who
therefore assumed that the "new" object was a pre-existing one; but the
DSS red images from 1990 Jan. 24 and 1989 Dec. 8, and the DSS infrared
image from 1998 Dec. 30, do not show this object, and Yamaoka surmised
that the blue DSS object could be a blue cluster region that is
extinguished by the light from the disk of UGC 4904 in the DSS red and
infrared images.  Yamaoka further surmised that the 2004 object might be a
luminous blue variable, such as 2000ch (cf. IAUC 7415, 7417, 7419, 7421),
or a reddened object behind the presumed blue cluster.  Yamaoka concluded
that the possibility of the variable object being a Galactic cataclysmic
variable could not be excluded, but additional observations to clarify the
puzzle in 2004 were not reported prior to the object's fading, despite
requests from the Central Bureau.


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

                         (C) Copyright 2006 CBAT
2006 October 11                  (CBET 666)               Daniel W. E. Green