{
  "subject": "GRB 230911A: Swift-XRT afterglow detection",
  "eventId": "GRB 230911A",
  "body": "P. D'Avanzo (INAF-OAB), D.N. Burrows (PSU), J. D. Gropp (PSU), S.\nDichiara (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U.\nLeicester), M.G. Bernardini (INAF-OAB), E. Ambrosi  (INAF-IASFPA)  and\nP.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the\nFermi/GBM-detected burst GRB 230911A, collecting 2.8 ks of Photon\nCounting (PC) mode data between T0+215.5 ks and T0+326.2 ks. \n\nAn uncatalogued X-ray source is detected consistent with the GOTO\nposition (GCN Circ. 34681) of the fading optical counterpart candidate,\nand this is therefore believed to be the afterglow.  The position of\nthis source (astrometrically enhanced by using the XRT-UVOT alignment\nand matching UVOT field sources to the USNO-B1 catalogue) is RA,\nDec=57.5027, -29.8259 which is equivalent to:\n\nRA (J2000): 03:50:0.65\nDec(J2000): -29:49:33.2\n\nwith an uncertainty of 3.4 arcsec (radius, 90% confidence). Position\nenhancement is described by Goad et al. (2007, A&A, 476, 1401) and\nEvans et al. (2009, MNRAS, 397, 177). This position is 3.1 arcsec from\nthe GOTO position.  \n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00021622.\nThe results of the full analysis of the XRT observations are available\nat https://www.swift.ac.uk/ToO_GRBs/00021622.\n\nThis circular is an official product of the Swift-XRT team.\n\n",
  "createdOn": 1694759377107,
  "bibcode": "2023GCN.34702....1D",
  "circularId": 34702,
  "submittedHow": "email-legacy",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>"
}