GCN Circular 11989
Subject
GRB 110428A : X-ray afterglow confirmation
Date
2011-05-02T19:15:40Z (13 years ago)
From
Andrea Melandri at Liverpool John Moores U <axm@astro.livjm.ac.uk>
A. Melandri, P. D'Avanzo, R. Margutti (INAF-OAB), B. Sbarufatti (INAF-
OAB/IASFPA) report on behalf of the Swift Team:
Swift continued to monitor the field of GRB 110428A (Vasileiou et
al., GCN 11982) in two different observations carried out on April
29th and May 1st, 2011.
In the final 18.49 ks of data (at a mean T-T0 = 2.07 days after the
burst event) we still detect Source #1 reported by Melandri et al.
(GCN 11984) with count rate of (1.6e-2 +/- 1.1e-3) cts/s, consistent
with a constant flux for this source.
Source #2 is no longer detected with a 3 sigma upper limit of 1.4e-3
cts/s. The probability for this source of having a constant flux is
8e-6. This is evidence of the fading of Source #2 with respect to the
XRT observation reported in Melandri et al. (GCN 11984). Therefore we
consider Source #2 as the X-ray afterglow of GRB 110428A.
This circular is an official product of the Swift-XRT team.