GCN Circular 6669
Subject
GRB 070724B: Swift-XRT afterglow candidates
Date
2007-07-25T23:50:43Z (17 years ago)
From
Pat Romano at OAB-Swift <patrizia.romano@brera.inaf.it>
P. Romano(Uni-Bicocca and OAB), J.A. Kennea(PSU), C. Guidorzi(Uni-Bicocca and OAB),
D. Burrows(PSU) report on behalf of the Swift-XRT team:
We have analysed the first two orbits of Swift-XRT data obtained for
GRB 070724B detected by SuperAGILE (Feroci et al., GCN Circ. 6668),
which include 3971s of Photon Counting (PC) mode data, beginning
on 2007-07-25 18:32:39 UT, 19.1 hours after the burst trigger time.
Using the PC data we found two sources within the SuperAGILE error circle,
at the following positions:
1) RA, Dec=17.48574, 57.67613, which is equivalent to
RA(J2000) = 01 09 56.58
Dec(J2000) = +57 40 34.1
with an estimated error radius of 4.5 arcsec (90% confidence).
This position lies 4.6 arcmin from the SuperAGILE position
(GCN Circ. 6668). The current observed 0.3-10 keV count rate is
(3.9+/-0.4)E-02 counts/s, which translates into a 0.3-10 keV flux of
~2E-12 erg/cm2/s (assuming a power-law with photon index=2 absorbed
by a column of NH=E21 cm-2).
2) RA, Dec= 17.51024, 57.81898, which is
RA(J2000) = 01 10 02.46
Dec(J2000) = +57 49 08.3
with an estimated error radius of 6.1 arcsec (90% confidence).
This position lies 9.5 arcmin from the SuperAGILE position.
The current observed 0.3-10 keV count rate is (0.6+/-0.2)E-02
counts/s, which translates into a 0.3-10 keV flux of ~3E-13 erg/cm2/s.
More data are being collected and a new circular will be issued
when the fading nature of these objects is established.
This circular is an official product of the XRT team.
[GCN OPS NOTE(26jul07): Per author's request, DB's affiliation was added,
"17.1 hours" was changed to "19.1 hours", and the exponent of the count rate
in the second source changed from "03" to "02".]