GCN Circular 17902
Subject
Swift trigger 642453 is not an astrophysical source
Date
2015-06-04T14:58:01Z (9 years ago)
From
Valerio D'Elia at ASDC <delia@asdc.asi.it>
V. D'Elia (ASDC), S. D. Barthelmy (GSFC), P. A. Evans (U. Leicester),
L. Izzo (URoma/ICRA) and M. H. Siegel (PSU) report on behalf of the
Swift team:
We have analysed 4.5 ks of Swift/XRT data for the Swift/BAT-detected
possible burst GRB 150604A (D'Elia et al. GCN Circ. 17901), collected
in Photon Counting mode, between 138 s and 21.6 ks after the BAT
trigger. No X-ray sources have been detected inside or close to the
Swift/BAT error region. The 3-sigma upper limit at the Swift/BAT
position is ~0.002 ct s^-1, corresponding to a 0.3-10 keV observed
flux of ~1e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).
Ground analysis of the BAT data for this trigger shows that the
significance of the initial detection has dropped below that
considered to be a valid trigger.
Swift/UVOT began settled observation of the field 142 s after the BAT
trigger. No new source is detected in the initial 1.4 ks of
observation down to a white magnitude limit of 20.9.
Therefore, this trigger is likely due to noise, and not due to
anything astrophysical.
This circular is an official product of the Swift team.