GCN Circular 6030
Subject
GRB070125: Swift-XRT Refined Analysis
Date
2007-01-26T06:37:06Z (17 years ago)
From
Judith Racusin at PSU <racusin@astro.psu.edu>
J. Racusin, L. Vetere (PSU) report on behalf of the Swift-XRT team:
The Swift-XRT began observing the field containing the IPN/BAT GRB 070125
(Hurley et al., GCN 6024) at 2007-01-25 20:18:48 UT, 46.7 ks after the
trigger. In four orbits of Photon Counting mode data totaling 5.4 ks we
detect an uncatalogued source at RA,Dec=117.82532,+31.1506 which is:
RA(J2000) = 7h 51m 18.08s
Dec(J2000) = +31d 09' 02.2"
with an uncertainty of 3.8 arcsec (90% containment). This is 85 arcseconds
from the initial position reported in GCN 6024, and 4.7 arcseconds from
the possible optical counterpart reported by Cenko et al. (GCN 6028).
The preliminary 0.3-10.0 keV lightcurve shows a fading behavior with a
decay index of 1.5 +/- 0.7. The XRT count rate is ~0.06 counts/s.
The PC spectrum is fit by an absorbed power-law with a photon index of 2.0
+/- 0.3. The absorption is at a level of 8.1e20 cm^-2, consistent with
Galactic absorption along the line of sight (4.8e20 cm^-2). The average
unabsorbed flux of the PC spectrum is 3.2e-12 ergs cm^-2 s^-1.
Assuming the X-ray emission continues to decline at the same rate, we
predict a 0.3-10.0 keV XRT count rate of 0.03 counts/s at T+24hr, and 0.01
counts/s at T+48hr, which corresponds to an observed flux of 1.5e-12 ergs
cm^-2 s^-1 and 5.3e-13 ergs cm^-2 s^-1, respectively.
Due to instrumental observing constraints, GRB070125 is not currently
being observed by Swift. Continued follow-up will likely occur over the
next few days.
This circular is an official product of the Swift-XRT team.