Central Bureau for Astronomical Telegrams
IAUC 6294: NGC 2363; 3C 279
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Circular No. 6294
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
Phone 617-495-7244/7440/7444 (for emergency use only)
NGC 2363
L. Drissen, J.-R. Roy and C. Robert, Departement de Physique,
Universite Laval, Quebec, communicate: "We report the discovery of an
unusually bright new object in the middle of the giant H II region
NGC 2363, based on Hubble Space Telescope WFPC2 images obtained on
Jan. 8. Preliminary reductions indicate V = 17.95, B-V roughly 0 for
the new object. This point source, which was then the brightest star
in NGC 2363 (absolute V about -10.0), was not visible on groundbased
CCD images obtained in Jan. 1991 and Oct. 1992 at the Canada-France-Hawaii
telescope; although crowding is severe in groundbased images, no
point source brighter than V about 22 was visible at that location.
WFPC2 images indicate that this object is a strong H alpha point
source, surrounded by a small (radius 0".09, or 1.5 pc at a distance
of 3.5 Mpc) H alpha shell. We suspect that this object is a Luminous
Blue Variable star in eruption (a la Eta Car). The coordinates
of this star, from our WFPC2 images, are R.A. = 7h28m43s.4, Decl. =
+69d11'24" (equinox 2000.0). This is 0".5 west and 1".3 north of the
'eastern knot' of NGC 2363 (Fig. 2 in Drissen et al. 1993, A.J. 106, 1460).
NGC 2363 is the brightest star-forming region in the Magellanic
irregular NGC 2366, a member of the M81 group."
3C 279
A. Wehrle, Infrared Processing and Analysis Center, California
Institute of Technology; and R. C. Hartman, Goddard Space Flight Center.
on behalf of the EGRET Team and Blazar Multiwavelength Consortium, report
that 3C 279 is undergoing a gamma-ray flare, as observed by EGRET on
the Compton Gamma Ray Observatory (CGRO): "The EGRET quicklook analysis
for Jan. 16-21 shows that 3C 279 was brighter in gamma rays (energy E
above 100 MeV) than in any observation since 1991, with a roughly
estimated flux of 1.3 to 1.4 x 10**-6 photon cm**-2 s**-1 at E > 100 MeV
(probable error roughly 20 percent). This is about a 10-sigma detection.
The CGRO observation of 3C 279 is being extended by one week, to Feb. 6,
to follow the development of this outburst. As part of an extensive
multiwavelength campaign, observations with other spacecraft (IUE, XTE,
ROSAT), as well as numerous groundbased observations, are currently
underway or have been concluded recently. Additional groundbased
observations are sought, especially at optical and near-infrared
wavelengths. T. Balonek, Colgate University, reports V = 15.3, R = 14.8
on Jan. 18; variations of one or more magnitudes, on timescales of days
to weeks, have been characteristic of this object during the past few years."
(C) Copyright 1996 CBAT
1996 January 25 (6294) Brian G. Marsden
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