{
  "bibcode": "2020GCN.26685....1P",
  "body": "M. Perri (ASDC), V. D'Elia (ASDC), B. Sbarufatti (PSU), D.N. Burrows\n(PSU), J. D. Gropp (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U.\nLeicester), A. D'Ai (INAF-IASFPA) and M. G. Bernardini (INAF-OAB)\nreport on behalf of the Swift-XRT team:\n\nWe have analysed 3.4 ks of XRT data for GRB 200107B (Bernardini et al.\nGCN Circ. 26661), from 908 s to 139.6 ks after the  BAT trigger. The\ndata are entirely in Photon Counting (PC) mode. The refined XRT\nposition is RA, Dec = 106.9086, -83.7162 which is equivalent to:\n\nRA (J2000): 07 07 38.07\nDec(J2000): -83 42 58.3\n\nwith an uncertainty of 4.0 arcsec (radius, 90% confidence).\n\nThe light curve can be modelled with a power-law decay with a decay\nindex of alpha=1.0 (+0.3, -0.4).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 1.9 (+0.5, -0.4). The\nbest-fitting absorption column is  2.8 (+2.4, -1.3) x 10^21 cm^-2,\nconsistent with the Galactic value of 1.5 x 10^21 cm^-2 (Willingale et\nal. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux\nconversion factor deduced from this spectrum  is 3.9 x 10^-11 (5.4 x\n10^-11) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     2.8 (+2.4, -1.3) x 10^21 cm^-2\nGalactic foreground: 1.5 x 10^21 cm^-2\nExcess significance: <1.6 sigma\nPhoton index:\t     1.9 (+0.5, -0.4)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00948219.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 26685,
  "createdOn": 1578579343000,
  "email": "paolo.davanzo@inaf.it",
  "subject": "GRB 200107B: Swift-XRT refined Analysis",
  "submitter": "Paolo D'Avanzo at INAF - OAB  <paolo.davanzo@inaf.it>",
  "eventId": "GRB 200107B"
}