Circular No. 6866
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)
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Phone 617-495-7244/7440/7444 (for emergency use only)


GRB 980329
     D. M. Cole, A. R. Cooray, J. M. Quashnock, D. E. Vanden Berk,
D. Q. Lamb, D. E. Reichart, G. T. Richards, K. Gloria, D. Long, and
T. Hoyes, University of Chicago, on behalf of the Astrophysical
Research Consortium (ARC), report:  "We made near-infrared
observations (IAUC 6860) of the BeppoSAX NFI error circle for GRB
980329 (IAUC 6853, 6854) between Apr. 1.167 and 1.277 UT, using the
ARC 3.5-m telescope (+ GRIM II) at Apache Point Observatory.  We
find no detectable object, down to a limiting magnitude of J = 20.9
+/- 0.5 (1 sigma) at the position of the variable radio source VLA
J0702+3850 proposed by Taylor et al.
(http://gcn.gsfc.nasa.gov/gcn/gcn3/040.gcn3 and IAUC 6864) to be
the radio afterglow from GRB 980329.  The measurement by Mannuci et
al. (http://gcn.gsfc.nasa.gov/gcn/gcn3/046.gcn3) of an object with
J = 19.2 (+0.8,-0.5) at the position of the radio source on Mar.
29.84-29.86 implies that this object dimmed by at least Delta(J) =
1.7 +/- 0.9 over about 2.4 days.  J-band images are available in
GIF and PostScript formats at ftp://astro.chicago.edu/pub/astro/GRB/."


eta CARINAE
     R. Viotti and P. Grandi, Istituto di Astrofisica Spaziale,
CNR, Rome; L. A. Antonelli and S. Rebecchi, BeppoSAX Science Data
Center (SDC), Rome; J. M. Muller, BeppoSAX SDC and Space Research
Organization of the Netherlands, Utrecht; and M. Villada,
Observatorio Astronomico, Cordoba, report: "eta Car was observed as
a target-of-opportunity with LECS and MECS onboard BeppoSAX over
Mar. 18.1-19.2 UT, during egress from the ongoing spectroscopic
event (IAUC 6849).  A preliminary comparison with the Dec. 1996
BeppoSAX observations revealed a large flux defect between 1.5 and
6 keV, indicating that the event was still in progress at high
energies.  The Fe-k line flux appears slightly weaker.  The
variation can be interpreted as due to a larger amount of absorbing
matter (about 3 times) from a hot 4.7-keV component, with only
minor changes of its unabsorbed flux.  Simultaneous optical
spectroscopy with the 2.15-m telescope of the Complejo Astronomico
El Leoncito provided the following emission-line equivalent widths
(in nm):  [NII] 575.5-nm, 1.0; He I 587.6-nm, 0.9; He I 667.8-nm,
1.1; He I 706.5-nm, 1.6.  This is about half of their intensity at
maximum, confirming the ending of the deeper part of the event."

                      (C) Copyright 1998 CBAT
1998 April 6                   (6866)            Daniel W. E. Green