TITLE: GCN CIRCULAR NUMBER: 43539 SUBJECT: GRB 260127A: Swift-XRT refined Analysis DATE: 26/01/28 10:27:05 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU), D.N. Burrows (PSU), S. Lanava (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), S. Campana (INAF-OAB), A. Melandri (INAF-OAR) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 9.4 ks of XRT data for GRB 260127A, from 226 s to 51.7 ks after the trigger. The data comprise 102 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The late-time light curve (from T0+5.2 ks) is consistent with a constant source of mean count rate 3.6e+00 ct/sec. A power-law fit gives an index of 3.08 (+0.03, -3.08). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.14 (+0.20, -0.19). The best-fitting absorption column is 8.0 (+4.6, -3.9) x 10^20 cm^-2, in excess of the Galactic value of 4.1 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.75 (+/-0.06) and a best-fitting absorption column of 1.32 (+0.21, -0.20) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.0 x 10^-11 (4.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.32 (+0.21, -0.20) x 10^21 cm^-2 Galactic foreground: 4.1 x 10^20 cm^-2 Excess significance: 7.6 sigma Photon index: 1.75 (+/-0.06) The results of the XRT-team automatic analysis are available at https://www.swift.ac.uk/xrt_products/01444088. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/43539. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...