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GCN Circular 326

GRB990510: X-ray afterglow
1999-05-14T02:55:53Z (25 years ago)
Erik Kuulkers at SRON <erikk@sron.nlw>
E. Kuulkers, J. Heise (SRON, Utrecht), L.A. Antonelli (Osservatorio
Astronomico di Roma), E. Costa, L. Piro (IAS, CNR, Rome), M.R. Daniele,
S. Rebecchi (SDC, Telespazio, Rome), G. Scotti (SOC, Telespazio, Rome),
G. Gennaro (OCC, Telespazio, Rome), F. Frontera (University of Ferrara,
Ferrara), report:

The BeppoSAX NFIs observed the region of GRB990510 (see also GCN 311) from
May 10.70 to May 12.22 UT, i.e. 8 to 44.5 hours after the BATSE trigger,
with a total MECS on source exposure time of 68 ksec.

We confirm that the strong X-ray source reported in GCN 311 is the X-ray
afterglow, and is designated as 1SAX J1338.1-8030. The position as derived
from the MECS observations (RA = 13 38 11, Dec = -80 29 58, J2000, 1
arcmin error radius) is consistent with both the WFC GRB position (IAUC
7160) and that for the optical afterglow source (GCN 310). The X-ray
afterglow decay light curve is not unlike that seen in previous X-ray
afterglow decays. We note that a previously uncatalogued weak (constant)
X-ray source lies about 3 arcmin away from the X-ray afterglow source,
with coordinates RA = 13 37 51, Dec = -80 26 53 (J2000, 1 arcmin error
radius), which we designate 1SAX J1337.8-8027.

This message may be cited.

[GCN OP NOTE: This circular was delayed in distribution due to an improper
vetting account.  It was received at 22:42 UT.  E.Kuulker's account
has been updated to reflect his new affiliation.]
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