TITLE:   GCN CIRCULAR
NUMBER:  7079
SUBJECT: GRB 071112C: Swift XRT refined analysis
DATE:    07/11/13 14:46:22 GMT
FROM:    Giulia Stratta at ASDC  <giulia.stratta@gmail.com>

G. Stratta (ASDC) , M. Perri (ASDC) and D. N. Burrows (PSU) report
on behalf of the Swift Team:

We have analysed the first 7 orbits of Swift-XRT data obtained
for GRB 071112C (Perri et al. GCN Circ.7059), totaling 281 s
of Windowed Timing (WT) data and 29.1 ks of Photon Counting (PC)
data.

Using 625 s of overlapping XRT Photon Counting mode and UVOT
V-band data, we find an astrometrically corrected X-ray position
(using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue):
RA,Dec =39.21220, 28.37102 which is equivalent to:

RA (J2000):  02 36 50.93
Dec (J2000): +28 22 15.7

with an uncertainty of 1.7 arcsec (radius, 90% confidence).
This is 1.0 arcsec from the previous XRT position, 0.7 arcmin
from the BAT position and 1.0 arcsec from the UVOT position
(Perri et al, GCN Circ. 7059).

The bright X-ray light-curve can be fit by a simple power-law,
with a decay index of 1.35 +/- 0.1.
Between about 400s and 1100s from the trigger, the data deviate
from the model, possibly pointing out a smooth re-brightening.

The WT data (91-372 seconds from trigger) can be modeled as an
absorbed power-law, with photon index of 1.7 +/- 0.1 and a total
absorbing column density consistent with the Galactic value of
NH=7.4e20 cm^-2 (Dickey & Lockmann 1990).
The 0.3-10 keV observed (unabsorbed) flux during this time is
4.4e-10(4.9e-10) erg cm^-2 s^-1.

Assuming the source continues to decay with the same decay
index of 1.35,we predict an XRT count rate of 3.0e-3 counts/s
at T+24 hours, which corresponds to an 0.3-10.0 keV observed
flux of 1.2e-13 ergs cm^-2 s^-1.

This circular is an official product of the Swift-XRT team.