GRB 990627

L.A. Antonelli, Osservatorio Astronomico di Roma, L. Nicastro, IFCAI, CNR, 
Palermo, M.R. Daniele, R. Ricci, BeppoSAX SDC, Telespazio, Roma
M. Stornelli, BeppoSAX OCC, Dataspazio, Roma, A. Paolino, BeppoSAX SOC,
Telespazio, Roma, E. Pian, E. Palazzi, ITESRE, CNR, G. Gandolfi and L. Piro
IAS, CNR on behalf of the BeppoSAX Team report:
 
"The BeppoSAX NFIs observed the region of GRB990627 (GCN 356
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 ) from
Jun 27.544 (8 hours after the BeppoSAX GRBM+WFC trigger) to Jun 28.864 UT
for a total MECS on source exposure time of 29 ksec.

A weak X-ray source (1SAX J0148.5-7704) lies within the 3' BeppoSAX WFC
error-circle (GCN 356
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 ). Source position is RA= 01 48 25.4 DEC= -77 04 38,
J2000, error radius 1' and is consistent with the radio source
AT J014832.6-770412 reported by Subrahmanyan et al.(GCN 357
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 ). 
This source shows a fading behaviour strongly suggesting we detected the
X-ray afterglow of GRB990627. 

This message may be cited."

Optical Observations of GRB990627


E. Rol (U. of Amsterdam), E. Palazzi, N. Masetti, E. Pian, F. Frontera
(TeSRE, CNR, Bologna), T.J. Galama, P.M. Vreeswijk, J. van Paradijs (U. of
Amsterdam), C. Kouveliotou (NASA/MSFC), G. Bakos, K. Sahu (STScI), P.
Sackett (U. of Groningen), J. Menzies (SAAO), L. Nicastro (IFCAI, CNR,
Palermo), E. Costa, (IAS, CNR, Rome), on behalf of a large collaboration
including the PLANET Team and the BeppoSAX GRB optical follow-up Team,
report:


"We have observed the error box of GRB990627 (Gandolfi, GCN #356
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 )
with the Sutherland 1.0m telescope (South Africa) in the R band
on June 28.138-28.193, for a total exposure time of 4200 sec.
Comparison of the summed image with the DSS (2nd Epoch Survey of the
UK Schmidt; RG610 filter) does not show evidence of any new source above
the DSS plate limit.

Photometry linked to the USNO-A1.0 star at RA = 01h 48m 15s.61, Dec = -77o
04' 37".1 (J2000), which has R = 15.8, implies a 3-sigma magnitude limit
of R ~ 21 for the sum image.

We have also inspected the positions of the four radio sources found by
Subrahmanyan et al. (GCN #357
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 ) in the GRB990627  error box.
No object brighter than our limiting magitude is seen at any of them.


This message can be cited."

R. Subrahmanyan (CSIRO), M. Wieringa (CSIRO), D. A. Frail (NRAO) and
S. R. Kulkarni (Caltech) report on behalf of a larger collaboration:

"We obtained an 11 hour integration with the Australia Telescope
Compact Array (ATCA) centered on June 28.67 UT at 4.8 GHz (including 3
hours at 4.9 GHz), and an 8 hour integration centered on June 28.76 UT
at 8.6 GHz. The ATCA was pointed at the BeppoSAX WFC position of 
GRB 990627 as given by Gandolfi (GCN 356
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 ).

Within the 3-arcmin WFC error circle there are four 6 cm sources above
5 sigma. We report these positions for the purpose of enabling
observations at other wavelengths. We are making no claims at this
time that any of these sources are the afterglow from GRB 990627.
Further ATCA observations are planned to determine which, if any, of
these sources are variable."

AT J014829.6-770653: RA 01:48:29.65, DEC -77:06:53.3 (J2000)
AT J014902.6-770517: RA 01:49:02.61, DEC -77:05:17.8 (J2000)
AT J014832.6-770412: RA 01:48:32.60, DEC -77:04:12.0 (J2000)
AT J014829.0-770253: RA 01:48:29.07, DEC -77:02:53.8 (J2000)

This message is citeable.

Giangiacomo Gandolfi on behalf of BeppoSAX Mission Scientist report:

A GRB (GRB 990627) was detected by the GRBM and WFC of BeppoSAX
on June 27, at 05:00:51 U.T.

Final coordinates from WFC are:
R.A.(2000)=27.1055
DEC(2000)=-77.0883

The error radius is 3'.


[GCN OP NOTE:  Format incompatibility problems prevented this from being
distributed in a timely fashion.  I am working on the problem, so that
hopefully this will not happen in the future.]