[vsnet-grb-info 2192] GRB050922B: refined XRT analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4031
SUBJECT: GRB050922B: refined XRT analysis
DATE:    05/09/23 16:39:11 GMT
FROM:    Olivier Godet at U.of Leicester  <og19 at star.le.ac.uk>

O. Godet, K.L. Page, J.P. Osborne (U. Leicester), D. N. Burrows (PSU),
N. Gehrels (NASA/GSFC), K. Hurley (Berkeley), M. Chester (PSU) report on
behalf of the Swift XRT team:

We have analyzed the Swift XRT data of the burst GRB 050922B from the
first 3 orbits (~4 ks). The refined coordinates are:

RA(J2000) =  00h 23min 13.2s
Dec(J2000) = -05d 36' 16.4"

with an uncertainty of 7 arcseconds radius (90% containment).  This
position is consistent with that reported by Norris et al. (GCN 4008).

Initial data show two flares peaking at ~370 s and ~846 s after the
trigger (T0), followed by a steep temporal decline decay (power law
decline index ~ 2.75+/-0.14). Later data from the second and third
orbits show a shallow decline with an temporal index ~ 0.95 +/- 0.41.

The X-ray spectrum after T0+5021 s is well fit by a power-law with
Gamma = 1.9+0.3/-0.2 (90% confidence) and a Galactic absorbing column
of 3.4e20 cm^-2.

If the light-curve is still unbroken at T0+24 h, the predicted
unabsorbed 0.3-10 keV flux is ~1.6e-13 erg cm^-2 s^-1.