[vsnet-grb-info 2927] GRB060206: Swift XRT observations of an unbroken powerlaw decay

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4764
SUBJECT: GRB060206: Swift XRT observations of an unbroken powerlaw decay
DATE:    06/02/15 23:34:08 GMT
FROM:    David Morris at PSU/Swift-XRT  <morris at astro.psu.edu>

D. C. Morris (PSU), C. Pagani (PSU), D. N. Burrows (PSU), J. A. Kennea 
(PSU) and K.Page (U. Leicester) report on behalf of the Swift XRT team:

The Swift XRT has continued to monitor the light curve of GRB060206 with 
data taken as late as T+8 days. Our complete X-ray dataset from T+5ks to 
T+700ks remains consistent with a single unbroken powerlaw decay with 
alpha=1.35+/-0.15. We note that there is apparent variability, both 
positive and negative, on the timescale of days in the X-ray lightcurve 
somewhat larger than is implied by simple counting statistics. Our data 
are not consistent, however, with a break to a slope of -2.2 at T+27 
hours and thus we cannot confirm the presence of the jet break reported 
in I-band observations by LaCluyze et al. (GCN 4750).

The XRT data remain consistent with the prediction by Palmer et al (GCN 
4597) of a jet break at 8.6 or 10.4 days (743ks or 899ks). The XRT 
countrate during the last observation, on February 14th, was 2e-3 cts/s, 
equivalent to a flux of approximately 1.5e-13 ergs/cm2/s. Observations 
are ongoing.

The XRT lightcurve can be viewed at 
http://www.swift.psu.edu/images/GRB060206.jpg

This circular is an official product of the Swift XRT Team.