[vsnet-grb-info 1790] GRB 050716: Refined XRT analysis.

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3630
SUBJECT: GRB 050716: Refined XRT analysis.
DATE:    05/07/16 19:30:32 GMT
FROM:    Cheryl Pauline Hurkett at Leicester U  <cph9 at star.le.ac.uk>

C. Hurkett, E. Rol, K. Page (U. Leicester), D. Burrows (PSU), J. Norris
(GSFC), K. Hurley (Berkeley) and N. Gehrels (GSFC) report for the Swift
XRT team:

We have analysed the XRT data for GRB 050716 (GCN 3623, Rol et al) taken
104 seconds after the trigger. PSF fitting of the candidate afterglow in
the photon counting (PC) mode observations yields a refined position of
(J2000)

RA 22:34:20.5
Dec +38:40:57.1

with an uncertainty of 6 arcseconds (90% containment). This position is
less than 1 arcsecond from the position reported in GCN 3624 (Kennea et
al).

XRT observations began in Windowed Timing (WT) mode 104 seconds after the
trigger and show a decline with a power-law decay index of 1.68
+/- 0.04 with flares at approximately 177 and 386 seconds.
The decay index appears to stay the same at least until 6000 seconds after
the trigger.

The spectrum between 104 and 517 seconds after the trigger (WT data) has
an average photon index of 1.32 (+/-0.04), with the absorption fixed at
its Galactic value of 1.1e21 cm^-2. There is no evidence at the present
time for excess absorption. The mean unabsorbed flux in WT mode at 230s
(logarithmic mean time) is 7.02 (+0.27/-0.24) x 1e-10 erg/cm^2/s in the
0.5-10.0 keV energy range