{
  "bibcode": "2017GCN.21180....1M",
  "body": "A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), S. J. LaPorte (PSU),\nJ.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), J.P. Osborne (U.\nLeicester), K.L. Page (U. Leicester), B. Mingo (U. Leicester), V.\nD'Elia (ASDC) and P.A. Evans report on behalf of the Swift-XRT team:\n\nWe have analysed 6.2 ks of XRT data for GRB 170531A (Evans et al. GCN\nCirc. 21170), from 254 s to 44.6 ks after the  BAT trigger. The data\nare entirely in Photon Counting (PC) mode. The best available XRT\nposition  (using the promptly downlinked event data, the XRT-UVOT\nalignment and matching UVOT field sources to the USNO-B1 catalogue) is\nRA, Dec = 121.2524, -14.0227 which is equivalent to:\n\nRA (J2000): 08 05 00.57\nDec(J2000): -14 01 21.8\n\nwith an uncertainty of 3.5 arcsec (radius, 90% confidence).\n\nThe light curve can be modelled with a power-law decay with a decay\nindex of alpha=0.62 (+0.20, -0.16).\n\nIf the light curve continues to decay with a power-law decay index of\n0.62, the count rate at T+24 hours will be 1.3 x 10^-3 count s^-1\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00755343.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 21180,
  "createdOn": 1496316782000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 170531A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 170531A"
}