{
  "body": "J.A. Kennea (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester),\nK.L. Page (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (SSDC &\nINAF-OAR), V. D'Elia (SSDC & INAF-OAR), S. Dichiara (PSU) and P.A.\nEvans (U. Leicester) reports on behalf of the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the Swift/BAT, MAXI\nand Fermi-GBM-detected burst GRB 240824B (GCN #37260, #37261, #37266,\n#37267) collecting 4.1 ks of Photon Counting (PC) mode data between\nT0+27.7 ks and T0+52.3 ks. \n\nTwo uncatalogued X-ray sources are detected consistent with being\nwithin 296 arcsec of the Swift/BAT position, of which one (\"Source 1\")\nis fading with 2.4 sigma significance and thus is believed to be the\nGRB afterglow. Using 732 s of PC mode data and 1 UVOT image, we find an\nenhanced XRT position (using the XRT-UVOT alignment and matching UVOT\nfield sources to the USNO-B1 catalogue): RA, Dec = 17.83675, +2.60999\nwhich is equivalent to:\n\nRA (J2000): 01h 11m 20.82s\nDec(J2000): +02d 36' 36.0\"\n\nwith an uncertainty of 4.5 arcsec (radius, 90% confidence). This\nposition is 36 arcsec from the Swift/BAT position. \n\nThe light curve can be modelled with a power-law decay with a decay\nindex of alpha=3.1 (+0.5, -2.1).\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00021705.\nThe results of the full analysis of the XRT observations are available\nat https://www.swift.ac.uk/ToO_GRBs/00021705.\n\nThis circular is an official product of the Swift-XRT team.\n\n",
  "circularId": 37270,
  "submittedHow": "email",
  "createdOn": 1724593129845,
  "bibcode": "2024GCN.37270....1K",
  "eventId": "GRB 240824B",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "subject": "GRB 240824B: Swift-XRT afterglow detection"
}