TITLE: GCN CIRCULAR NUMBER: 42493 SUBJECT: GRB 251025B: Swift-XRT confirmation of fading DATE: 25/10/27 20:42:45 GMT FROM: P.A. Evans at U. Leicester pae9@leicester.ac.uk

P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:

Swift-XRT has reobserved the X-ray afterglow of GRB 251025B (Hussein et al., GCN Circ. 42437, Beardmore et al., GCN Circ. 42245), gathering a further 2.6 ks of exposure from T0+131 ks to T0+154 ks.

The X-ray source is detected but has faded significantly, from 0.30 +/- 0.02 ct/sec to 0.009 (+0.003, -0.002) ct/sec (0.3-10 keV), further confirming its identity as the afterglow of this GRB. The best-fitting power-law decay index is 0.95 (+0.15, -0.12).

This circular is an official product of the Swift-XRT team.

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