[vsnet-grb-info 2392] GRB050911A: further steepening in the X-ray light curve

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4229
SUBJECT: GRB050911A: further steepening in the X-ray light curve
DATE:    05/11/09 16:49:51 GMT
FROM:    Sergio Campana at INAF-OAB  <campana at merate.mi.astro.it>

S. Campana (INAF-OAB), T. Mineo (INAF-IASFPA), G. Tagliaferri (INAF-OAB),
V. Mangano (INAF-IASFPA), P. Romano (INAF-OAB) on behalf of the
Swift/XRT team:

After the analysis of the full initial dataset, we see that the
light curve of GRB051109A shows a further break besides the one
already highlighted previously (Campana et al., GCN 4228).
This second break is relatively unconstrained occurring between
the first (<200 s) and the second (>3000 s) Swift orbit.
In the first part the decay is very steep with index
alpha_1=-3.1 +/- 0.6 (90% containment, as reported). The second
power law contains basically no data and it is only loosely
constrained. The third power law has alpha_3=-1.2 +/- 0.1.
The reduced chi2 is 1.2 (57 dof).
The expected flux at 1 day is 8e-13 erg cm^-2 s^-1.