Skip to main content
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 28512

GRB 200925B: Swift-XRT refined analysis update
2020-09-27T11:32:20Z (4 years ago)
Andy Beardmore at U Leicester <>
A.P. Beardmore (U. Leicester) and S. B. Cenko (GSFC) report on
behalf of the Swift-XRT team:

An additional 4.9 ks of Swift-XRT Photon Counting mode data have
been collected on GRB 200925B (Cenko et al.  GCN Circ. 28499,
Sbarufatti et al. GCN Circ. 28508), bringing the total XRT
exposure to 10 ks, from 87 s to 86.3 ks after the BAT trigger.
The late time X-ray light curve from T0+29.2 ks to 86.3 ks
is now decaying with a power-law decay slope of 1.1 +/- 0.4.

If the light curve continues to decay at the same rate than
the predicted count rate at T0+3 days will be 3.4e-03 count/sec,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 
1.05 x 10^-13 (1.28 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at

This circular is an official product of the Swift-XRT team.
Looking for U.S. government information and services? Visit