[vsnet-grb-info 2489] GRB 051211: Swift XRT upper limit

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4326
SUBJECT: GRB 051211: Swift XRT upper limit
DATE:    05/12/11 19:32:52 GMT
FROM:    David Burrows at PSU/Swift  <dxb15 at psu.edu>

G. Cusumano (INAF-IASF), D.N. Burrows, S. Hunsberger, C. Pagani (PSU), V. 
La Parola, and V. Mangano (INAF-IASF) report on behalf of the Swift XRT team:

The Swift XRT began observing HETE-discovered GRB 051211 (Atteia et al., 
GCN 4324) at 14:43:21 UT on 11 December 2005.  In the first two orbits we 
accumulated 3330 s of exposure time.  We find no X-ray counterpart within 
the HETE/SXC error circle, with a 3 sigma upper limit of 3.19E-3 
counts/s  (2.0 E-13 erg/s/cm/cm).  We note that this is considerably 
fainter than the typical Swift afterglow at this same time frame, though 
not inconsistent with the fainter Swift afterglows (Nousek et al. 2005, 
astroph/0508332).  Observations will be terminated at about 19:30 UT on 11 
December to prevent overheating of the XRT detector.