TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3441
SUBJECT: XRF 050509c: Swift XRT Upper Limit
DATE:    05/05/20 16:45:22 GMT
FROM:    Sergio Campana at INAF-OAB  <campana@merate.mi.astro.it>

S. Campana (INAF-OAB), C. Pagani (INAF-OAB, PSU), D.N. Burrows (PSU)
and N. Gehrels (NASA/GSFC) report on behalf of the Swift XRT team:

The Swift XRT observed the HETE II burst XRF 050509c for ~4ks from
07:00 UT to 21:35 UT on 18 May 2005 and for ~19 ks from 00:18 UT to 23:25 UT
on 19 May 2005.

We did not detect any source in either observation in a 20
arcsec radius circle centred at the position of the optical counterpart
identified by Gorosabel et al 2005 (GCN 3425). Combining data from the two
observations, we obtain 23.1 ks of good data after normal data screening.
The 3 sigma upper limit on the count rate is of 8.4e-4 counts/s 
(0.2-10.0 keV).
Assuming a Crab-like spectrum and a Galactic column of 7.1e20 cm-2, this
corresponds to an upper limit on the unabsorbed flux of ~3e-14 
ergs/cm2/s (0.5-10.0 keV).