TITLE:   GCN CIRCULAR
NUMBER:  3426
SUBJECT: GRB 050504: Swift XRT afterglow candidate has faded
DATE:    05/05/16 17:39:05 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea@astro.psu.edu>

J. A. Kennea, D. N. Burrows (PSU), B. Zhang (UNLV) and N. Gehrels
(NASA/GSFC) report on behalf of the Swift XRT team:

Swift perfomed a follow up observation of the X-ray afterglow candidate of 
GRB050504 repored in GCN 3359. The new observation began on 01:38:23UT on 
14th May 2005, and Swift-XRT collected 7 ks of photon counting mode data. 
Analysis of the ground processed data on GRB050504 from the second epoch 
observations reveal no detection of the source found in the first epoch. 
The 90% confidence level upper limit is 7.9 x 10^-4 cts/s compared to a 
source brightness in the first epoch of 3.5+/-0.7 x 10^-3 cts/s.

We therefore conclude that the X-ray source reported in GCN 3359 has 
faded, and is most likely the X-ray afterglow of GRB050504.