TITLE: GCN CIRCULAR NUMBER: 43017 SUBJECT: GRB 251205A: Swift-XRT refined Analysis DATE: 25/12/07 03:50:01 GMT FROM: Phil Evans at U of Leicester pae9@star.le.ac.uk
S. Dichiara (PSU), J.A. Kennea (PSU), D.N. Burrows (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), C. Salvaggio (INAF-OAB), M. Ferro (INAF-OAB), R. Brivio (INAF-OAB) and P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 6.3 ks of XRT data for GRB 251205A, from 129 s to 94.1 ks after the trigger. The data comprise 352 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+9.7 ks) can be modelled with a power-law decay with a decay index of alpha=0.77 (+0.12, -0.11).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.14 (+/-0.06). The best-fitting absorption column is 5.6 (+1.3, -1.2) x 10^20 cm^-2, in excess of the Galactic value of 1.2 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.95 (+0.16, -0.15) and a best-fitting absorption column of 3.8 (+3.5, -2.6) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (3.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus: Total column: 3.8 (+3.5, -2.6) x 10^20 cm^-2 Galactic foreground: 1.2 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.95 (+0.16, -0.15)
The results of the XRT-team automatic analysis are available at https://www.swift.ac.uk/xrt_products/01420873.
This circular is an official product of the Swift-XRT team.
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