GCN Circular 429
Subject
GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
Date
1999-10-29T14:32:47Z (25 years ago)
From
Jean int Zand at SRON <jeanz@sron.nl>
J. in 't Zand, Space Research Organization Netherlands (SRON),
Utrecht; L.A. Antonelli, Osservatorio Astronomico di Roma; L. Kuiper, SRON;
S. Rebecchi, M. Stornelli, D. Ricci, BeppoSAX Science Operations Center,
Telespazio, Rome; and G. Gandolfi, Istituto di Astrofisica Spaziale, CNR,
Rome, update the information given in GCN Circ. 427.: "GRB 991014 was
observed with the Narrow Field Instruments on board BeppoSAX on two
occasions: Oct. 15.4-16.4 UT (0.5-1.5 d after the burst) and Oct.
24.8-25.9 (9.9-11.0 d after the burst). In the 2-10 keV images from both
Medium-Energy Concentrator Spectrometer units 2 and 3, two sources only
3' apart are within the combined WFC/IPN error regions of the burst (IAUC
7281, GCN 419). Their positions are R.A. = 6h51m03s, Decl. = +11d36'05"
(SAX J0651.0+1136 = S1 in GCN 427; Eq. 2000.0; error radius 1.5') and
R.A. = 6h50m57s, Decl. = +11d33'13" (SAX J0651.0+1133 = S2 in GCN 427;
error radius 1'). The first source is not detected in the second
observation. The 3 sigma upper limit translates to a decay by at least a
factor of 2.2. The second source did not change significantly, the
intensity change is 10+/-20%. Therefore, we identify SAX J0651.0+1136 as
the X-ray afterglow of GRB 991014.