[vsnet-grb-info 5155] GRB 071003: XRT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6855
SUBJECT: GRB 071003: XRT refined analysis
DATE:    07/10/06 16:01:59 GMT
FROM:    Rhaana Starling at U of Leicester  <rlcs1 at star.le.ac.uk>

R. Starling, P.A. Evans, K.L. Page, A.P. Beardmore (U. Leicester) and P. 
Schady (MSSL/UCL) report on behalf of the Swift team:

We report on Swift XRT observations of the GRB 071003 (trigger=292934,
Schady et al., GCN  Circ. 6837) beginning 22.3 ks and ending 244 ks after
the BAT trigger, totalling 29.6 ks of photon counting mode data.

We refine the position given in Starling and Schady, GCN Circ. 6845, to
RA,Dec(J2000) = 301.85090, 10.947225 deg, equivalent to:
RA(J2000) =  20h 07m 24.22s
Dec(J2000)= +10d 56' 50.0"
with an error of radius 5.5 arcseconds (90%, including boresight
uncertainties). This is 1.3 arcseconds away from the initial XRT position 
and 2.3 arcseconds from the optical transient (Li, GCN Circ. 6838).

The light curve is best fit with a broken power law with initial decay
slope of alpha_1 = 1.0(+0.2/-0.4), T_bk = 3.9(+0.8/-0.4)E4 s and 
alpha_2 = 1.8(+/-0.4).

The spectrum can be modelled with a power law of photon index Gamma =
2.1(+/-0.2) with fixed Galactic absorption of nH = 1.4E21 cm^-2 and
allowing for intrinsic absorption at z = 1.1 (lower limit from Perley et
al., GCN Circ. 6850) which we find is consistent with zero.
The mean observed (unabsorbed) 0.3-10 keV flux is 7E-13 (1E-12) 
erg/cm^2/s.
The count to flux conversion from these data is approximately 1 ct/s =
4.7E-11 erg/cm^2/s.
      
This is an official product of the Swift XRT team.