GCN Circular 685
Subject
X-ray Afterglow of GRB 000529
Date
2000-06-01T21:06:28Z (25 years ago)
From
Marco Feroci at IAS/CNR Frascati <feroci@ias.rm.cnr.it>
GRB000529: candidate X-ray afterglow
M. Feroci, G. Gandolfi, E. Costa, L. Piro, P. Soffitta (IAS, CNR, Rome),
L.A. Antonelli (OAR, Rome), L. Salotti (ASI, Rome), A. Coletta,
G. Celidonio, G. D'Andreta, M.R. Daniele, M. Stornelli (Telespazio, Rome),
F. Frontera, E. Pian (ITESRE, CNR, Bologna),
L. Nicastro (IFCAI, CNR, Palermo),
J.J.M. in 't Zand, J. Heise, M.J. Smith, J.M. Muller (SRON, Utrecht),
on behalf of the BeppoSAX GRB Team, report:
"The WFC error box (GCN #676) of GRB 000529 was observed by the
Narrow Field Instruments starting about 7.5 hours after the GRB.
A preliminary analysis of the first 23 ks of this observation
reveals a previously unknown weak X-ray source, 1SAX J0009.8-6128
at the position RA = 00h 09m 48.3s Dec = -61d 27' 53", with a
conservative error radius of 2 arcminutes.
No other source is significantly detected in the field.
By dividing the available observation in two portions, the source
is detected only in the first ~11ks with a count rate of
(4.1+-1.0)E-3 count/s, corresponding to 2.8E-13 erg/cm2/s
(assuming a Crab-like energy spectrum). The lack of source detection
in the second ~12ks makes the new source a reasonable candidate as the
X-ray afterglow of GRB 000529.
The position lies at 4.9 arcminutes from the WFC refined
error box, and it therefore only partially overlaps with it.
We note that the position of the NFI source is consistent with
the IPN annulus for this GRB (GCN #680).
This message may be quoted in publications."