TITLE: GCN CIRCULAR NUMBER: 41314 SUBJECT: Corrected Swift-XRT Refined Analysis of GRB 250809A DATE: 25/08/10 10:35:32 GMT FROM: K.L. Page at U Leicester klp5@leicester.ac.uk

K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team:

GCN Circ. 41313 provided an incomplete automatic modelling of the XRT light-curve of GRB 250809A. The first snapshot of data is dominated by a large flare, peaking at 240 s after the BAT trigger. The underlying decay can be modelled as a power-law with alpha = 3.0 +/- 0.2.

If the light curve continues to decay with a power-law decay index of 3.0, the count rate at T+24 hours will be 2.3 x 10^-8 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.3 x 10^-20 (1.5 x 10^-19) erg cm^-2 s^-1.

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

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