{
  "bibcode": "2018GCN.23236....1D",
  "body": "A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), S. J. LaPorte (PSU),\nJ.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), S.L. Gibson (U.\nLeicester), Z. Liu (NAOC / U. Leicester), J.P. Osborne (U. Leicester),\nP. D'Avanzo (INAF-OAB) and P.A. Evans (U. Leicester) report on behalf\nof the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the\nFermi/LAT-detected burst GRB 180914B (Bissaldi et al. GCN Circ. 23232)\nin a series of observations tiled on the sky. The total exposure time\nis 4.1 ks, distributed over 6 tiles; the maximum exposure at a single\nsky location was 1.3 ks. The data were collected between T0+82.8 ks and\nT0+93.8 ks, and are entirely in Photon Counting (PC) mode. \n\nAn uncatalogued X-ray source is detected and is above the RASS limit,\nand is therefore likely the GRB afterglow. Using 579 s of PC mode data\nand 2 UVOT images, we find an enhanced XRT position (using the XRT-UVOT\nalignment and matching UVOT field sources to the USNO-B1 catalogue):\nRA, Dec = 332.35648, +25.06314 which is equivalent to:\n\nRA (J2000): 22h 09m 25.56s\nDec(J2000): +25d 03' 47.3\"\n\nwith an uncertainty of 3.4 arcsec (radius, 90% confidence). This\nposition is 12.1 arcmin from the Fermi/LAT position.  The source has a\nmean count rate of 6.2e-02 ct/sec; we cannot determine at the present\ntime whether it is fading.\n\nThe results of the XRT-team automatic analysis of the likely afterglow\nare at http://www.swift.ac.uk/xrt_products/TILED_GRB00075/Source2.php.\nThe results of the full analysis of the tiled XRT observations are\navailable at http://www.swift.ac.uk/xrt_products/TILED_GRB00075.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 23236,
  "createdOn": 1537050101000,
  "email": "paolo.davanzo@brera.inaf.it",
  "subject": "GRB 180914B: Swift-XRT afterglow detection",
  "submitter": "Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>",
  "eventId": "GRB 180914B"
}