Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

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.
Looking for U.S. government information and services? Visit USA.gov