TITLE: GCN CIRCULAR NUMBER: 40323 SUBJECT: GRB 250430A: Swift-XRT refined Analysis DATE: 25/05/02 13:27:07 GMT FROM: Phil Evans at U of Leicester pae9@star.le.ac.uk
R. Brivio (INAF-OAB), M. A. Williams (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAR) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
We have analysed 1.4 ks of XRT data for GRB 250430A, from 166 s to 1.9 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode.
The light curve can be modelled with a power-law decay with a decay index of alpha=0.37 (+0.13, -0.14).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.89 (+0.26, -0.24). The best-fitting absorption column is 1.7 (+0.9, -0.8) x 10^21 cm^-2, in excess of the Galactic value of 9.6 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 3.8 x 10^-11 (4.8 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus: Total column: 1.7 (+0.9, -0.8) x 10^21 cm^-2 Galactic foreground: 9.6 x 10^20 cm^-2 Excess significance: 1.7 sigma Photon index: 1.89 (+0.26, -0.24)
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01308754.
This circular is an official product of the Swift-XRT team.
View this GCN Circular online at https://gcn.nasa.gov/circulars/40323. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...