TITLE: GCN CIRCULAR NUMBER: 42665 SUBJECT: GRB 251112A: Swift-XRT refined Analysis DATE: 25/11/13 10:27:12 GMT FROM: Phil Evans at U of Leicester <pae9@star.le.ac.uk> 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), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: We have analysed 847 s of XRT data for GRB 251112A, from 90 s to 939 s after the Swift trigger. The data comprise 64 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The refined XRT position is RA, Dec = 274.0697, +24.1535 which is equivalent to: RA (J2000): 18h 16m 16.72s Dec(J2000): +24d 09' 12.5" with an uncertainty of 4.1 arcsec (radius, 90% confidence). The light curve can be modelled with a power-law decay with a decay index of alpha=3.14 (+0.34, -0.30). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 3.3 (+/-0.4). The best-fitting absorption column is 4.9 (+1.3, -1.1) x 10^21 cm^-2, in excess of the Galactic value of 1.8 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.2 x 10^-11 (1.1 x 10^-10) erg cm^-2 count^-1. A summary of the WT-mode spectrum is thus: Total column: 4.9 (+1.3, -1.1) x 10^21 cm^-2 Galactic foreground: 1.8 x 10^21 cm^-2 Excess significance: 4.6 sigma Photon index: 3.3 (+/-0.4) If the light curve continues to decay with a power-law decay index of 3.14, the count rate at T+24 hours will be 7.8 x 10^-9 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.7 x 10^-19 (8.4 x 10^-19) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at https://www.swift.ac.uk/xrt_products/01413695. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/42665. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...