GCN Circular 42442

S. Dichiara (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U.
Leicester), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), C.
Salvaggio (INAF-OAB), J.A. Kennea (PSU), D.N. Burrows (PSU) and P.A.
Evans report on behalf of the Swift-XRT team:

We have analysed 4.4 ks of XRT data for GRB 251024A, from 113 s to 56.4
ks after the   trigger. The data comprise 30 s in Windowed Timing (WT)
mode (the first 10 s were taken while Swift was slewing) with the
remainder in Photon Counting (PC) mode.  The late-time light curve
(from T0+4.5 ks) is consistent with a constant source of mean count
rate 4.5e-01 ct/sec. A power-law fit gives an index of -0.14 (+0.15,
-0.14).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.06 (+0.16, -0.11). The
best-fitting absorption column is  consistent with the Galactic value
of 3.7 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 3.2 x 10^-11 (3.6 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     3.7 (+/-2.8) x 10^20 cm^-2
Galactic foreground: 3.7 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     2.06 (+0.16, -0.11)

The results of the XRT-team automatic analysis are available at
https://www.swift.ac.uk/xrt_products/01406589.

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