{
  "bibcode": "2021GCN.30416....1B",
  "body": "D.N. Burrows (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U.\nLeicester), K.L. Page (U. Leicester), T. Sbarrato (INAF-OAB), P.\nD'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), J. D. Gropp (PSU) and\nB. Sbarufatti report on behalf of the Swift-XRT team:\n\nWe have analysed 6.8 ks of XRT data for GRB 210708A (Sbarufatti et al.\nGCN Circ. 30413), from 85 s to 22.8 ks after the  BAT trigger. The data\nare entirely in Photon Counting (PC) mode. The refined XRT position is\nRA, Dec = 173.7372, -49.1515 which is equivalent to:\n\nRA (J2000): 11 34 56.92\nDec(J2000): -49 09 05.4\n\nwith an uncertainty of 7.0 arcsec (radius, 90% confidence).\n\nThe light curve can be modelled with a power-law decay with a decay\nindex of alpha=1.76 (+0.30, -0.65).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 2.5 (+0.4, -0.3). The\nbest-fitting absorption column is  3.0 (+1.2, -1.0) x 10^21 cm^-2, in\nexcess of the Galactic value of 1.6 x 10^21 cm^-2 (Willingale et al.\n2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion\nfactor deduced from this spectrum  is 3.0 x 10^-11 (5.8 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     3.0 (+1.2, -1.0) x 10^21 cm^-2\nGalactic foreground: 1.6 x 10^21 cm^-2\nExcess significance: 2.2 sigma\nPhoton index:\t     2.5 (+0.4, -0.3)\n\nIf the light curve continues to decay with a power-law decay index of\n1.76, the count rate at T+24 hours will be 8.8 x 10^-6 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.6 x\n10^-16 (5.1 x 10^-16) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/01059460.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 30416,
  "createdOn": 1625740953000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 210708A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 210708A"
}