GCN Circular 3426
Subject
GRB 050504: Swift XRT afterglow candidate has faded
Date
2005-05-16T17:39:05Z (19 years ago)
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.