[vsnet-grb-info 2510] GRB051211B: XRT refined analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4347
SUBJECT: GRB051211B: XRT refined analysis
DATE:    05/12/13 16:04:25 GMT
FROM:    Valentina La Parola at INAF-IASPA  <laparola at ifc.inaf.it>

V. La Parola, V. Mangano, G. Cusumano (INAF-IASF), C. Pagani (INAF-OAB), and D. N. 
Burrows (PSU), D. Hinshaw (GSFC-SPSYS), F. Marshall (GSFC),  report on behalf of the Swift XRT team:

We report on further analysis of the XRT observation of GRB051211B (Mereghetti et al., GCN 4327; Pagani et al, GCN 4332; La Parola et al., GCN 4338).

The XRT observation begins 10.8 ksec after the INTEGRAL trigger.
We see a flat phase with a break at 18 ksec from the burst trigger, then the X-ray light-curve decays as a powerlaw with slope -1.16 +/- 0.18. 

The spectrum of the PC data can be modelled with an absorbed power-law
with photon index Gamma = 2.0+/-0.3 (90% confidence level).
The absorbing column best fit value is (4.1 +/- 1.3)e21 cm-2, consistent with the Galactic value of 3.3e21 cm-2 

The flux at T+24h is 4.4e-13 erg cm^-2 s^-1