TITLE: GCN CIRCULAR NUMBER: 24608 SUBJECT: GRB 190519A: Swift-XRT refined Analysis DATE: 19/05/20 02:18:41 GMT FROM: Phil Evans at U of Leicester A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and T.N. Ukwatta report on behalf of the Swift-XRT team: We have analysed 7.0 ks of XRT data for GRB 190519A (Ukwatta et al. GCN Circ. 24595), from 91 s to 46.8 ks after the BAT trigger. The data comprise 100 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 24597). The late-time light curve (from T0+13.7 ks) can be modelled with a power-law decay with a decay index of alpha=1.33 (+/-0.28). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.34 (+0.20, -0.18). The best-fitting absorption column is 6.5 (+1.2, -1.1) x 10^21 cm^-2, in excess of the Galactic value of 4.3 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.79 (+0.13, -0.12) and a best-fitting absorption column of 6.8 (+1.1, -1.0) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.9 x 10^-11 (7.5 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 6.8 (+1.1, -1.0) x 10^21 cm^-2 Galactic foreground: 4.3 x 10^21 cm^-2 Excess significance: 4.3 sigma Photon index: 1.79 (+0.13, -0.12) If the light curve continues to decay with a power-law decay index of 1.33, the count rate at T+24 hours will be 0.020 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.0 x 10^-12 (1.5 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00904394. This circular is an official product of the Swift-XRT team.