TITLE: GCN CIRCULAR NUMBER: 43492 SUBJECT: GRB 260120B: Swift-XRT refined Analysis DATE: 26/01/21 20:20:55 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> M. Ferro (INAF-OAB), R. Brivio (INAF-OAB), A. D'Ai (INAF-IASFPA), S. Lanava (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 5.6 ks of XRT data for GRB 260120B, from 130 s to 29.5 ks after the trigger. The data comprise 13 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 light curve can be modelled with a power-law decay with a decay index of alpha=0.84 (+/-0.06). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.97 (+0.29, -0.27). The best-fitting absorption column is 2.1 (+1.2, -1.0) x 10^21 cm^-2, in excess of the Galactic value of 7.4 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 3.7 x 10^-11 (5.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.1 (+1.2, -1.0) x 10^21 cm^-2 Galactic foreground: 7.4 x 10^20 cm^-2 Excess significance: 2.4 sigma Photon index: 1.97 (+0.29, -0.27) The results of the XRT-team automatic analysis are available at https://www.swift.ac.uk/xrt_products/01442454. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/43492. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...