Circular No. 6611
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, 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)
URL http://cfa-www.harvard.edu/cfa/ps/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)

GS 1826-238
     P. Ubertini, A. Bazzano, M. Cocchi, and L. Natalucci, Istituto
di Astrofisica Spaziale, CNR, Frascati; J. Heise, R. Jager, and J.
in 't Zand, Space Research Organisation of the Netherlands (SRON),
Utrecht; J. M. Muller and M. Smith, SRON and BeppoSAX Scientific
Data Center, Rome; and G. Celidonio, A. Coletta, R. Ricci, P.
Giommi, D. Ricci, M. Capalbi, M. T. Menna, and S. Rebecchi,
BeppoSAX, Rome, report:  "The Ginga transient GS 1826-24 was
detected beginning on Mar. 29.61 UT at a flux on the order of 12
mCrab in the range 1.8-8.3 keV with the Wide Field Camera onboard
the BeppoSax satellite, during a deep galactic-center observation.
The preliminary source position is R.A. = 18h29m28s, Decl. =
-23o48'.0 (equinox 2000.0), with a 3' error radius.  During the
follow-up monitoring of the source, at least three bursts were
detected, on Mar. 30.092 (peak flux 350 mCrab), 31.694 (520 mCrab),
and 31.943 (480 mCrab).  All bursts show a duration time of about
150 s.  On the basis of the bursting behavior, we suggest that the
source is a neutron-star system (as possibly first indicated by the
OSSE high-energy spectrum; Strickman et al. 1996, A.Ap. Suppl. Ser.
120, 217)."


GRB 970228
     S. Klose and B. Stecklum, Thuringer Landessternwarte
Tautenburg, and R. Tuffs, Max-Planck-Institut fur Kernphysik,
Heidelberg, write:  "The error box of GRB 970228 was surveyed with
the Calar Alto 3.5-m telescope (f/10) on Mar. 17.8 UT using the
near-infrared camera MAGIC (0".81 pixels, seeing < 1".5,
photometric sky).  At the position of the optical transient
reported on IAUC 6584, a source is detected (5 sigma) in the J band
(magnitudes J = 21.0, H > 20.0, K > 19.5).  We cannot decide,
however, whether this is the reported underlying galaxy (Groot et
al. and Metzger et al., IAUC 6588) or the fading infrared
counterpart of the optical transient (or both).  The J-band image
can be accessed via http://www.tls-tautenburg.de/research.html."


COMET C/1997 D1 (MUELLER)
     Visual m1 estimates:  Mar. 1.80 UT, 14.0 (K. Hornoch,
Lelekovice, Czech Republic, 0.35-m reflector); 4.27, 13.4 (A.
Hale, Cloudcroft, NM, 0.41-m reflector); 28.91, 13.6 (J. Carvajal,
Teruel, Spain, 0.44-m reflector); Apr. 2.92, 13.4 (M. Meyer,
Frauenstein, Germany, 0.25-m reflector).

                      (C) Copyright 1997 CBAT
1997 April 4                   (6611)            Daniel W. E. Green