[AAVSO-HEN] Swift XRT Observation of GRB 060402C

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4672
SUBJECT: Swift XRT Observation of GRB 060402C 
DATE:    06/02/05 05:02:35 GMT
FROM:    Dirk Grupe at PSU/Swift-XRT  <grupe at astro.psu.edu>

D. Grupe, J. A. Kennea, and D. N. Burrows (PSU) report on behalf of the 
Swift XRT team:

The Swift XRT began observing the field of BAT trigger 180274 (presumed 
to be GRB 060204C) at 20:36:20 (157 seconds after the BAT trigger).  In 
the first 4 orbits of data (total exposure 8.0 ks) we find no evidence 
for any source within the BAT error circle.

We place an upper limit of 1e-14 ergs/s/cm2 on any X-ray counterpart to 
this event.

We do find a fairly bright source 8 arcminutes from the BAT position at 
(RA, Dec, J2000) =  (06:12:23.0, +70 12 42.9), but this object is not 
fading and appears to be coincident with an object in the DSS (but not 
in the ROSAT All-sky survey).

We note that it is extremely unusual for the XRT to slew promptly to a 
long GRB and not find a bright X-ray source in the field of view.  In 
fact, there have been no previous cases in which the XRT slewed to a 
long GRB field in less than 300 seconds and did not detect an afterglow.

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