[vsnet-grb-info 4232] GRB070125: Swift-XRT Refined Analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6030
SUBJECT: GRB070125: Swift-XRT Refined Analysis
DATE:    07/01/26 06:37:06 GMT
FROM:    Judith Racusin at PSU  <racusin at 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.