{
  "circularId": 38098,
  "bibcode": "2024GCN.38098....1K",
  "body": "J.A. Kennea (PSU), D.N. Burrows (PSU), A.P. Beardmore (U. Leicester),\nJ.P. Osborne (U. Leicester), M. Perri (SSDC & INAF-OAR), V. D'Elia\n(SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), M. A. Williams (PSU) and\nP.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the BAT/GUANO\nlocalisation of the Fermi/GBM-detected burst GRB 241105A, collecting\n3.9 ks of Photon Counting (PC) mode data between T0+38.3 ks and T0+62.2\nks. \n\nTwo uncatalogued X-ray sources are detected consistent with being\nwithin 296 arcsec of the BAT/GUANO position, of which one (\"Source 1\")\nis fading with 2.2 sigma significance and thus is believed to be the\nGRB afterglow. Using 794 s of PC mode data and 2 UVOT images, we find\nan enhanced XRT position (using the XRT-UVOT alignment and matching\nUVOT field sources to the USNO-B1 catalogue): RA, Dec = 66.24484,\n-49.75181 which is equivalent to:\n\nRA (J2000): 04h 24m 58.76s\nDec(J2000): -49d 45' 06.5\"\n\nwith an uncertainty of 4.9 arcsec (radius, 90% confidence). This\nposition is 18 arcsec from the BAT/GUANO position (DeLaunay et al., GCN\nCirc. 38091), and is consistent with the GOTO optical counterpart\n(Julakanti et al., GCN Circ. 38088).\n\nThe light curve can be modelled with a power-law decay with a decay\nindex of alpha=3.32 (+0.05, -2.26).\n\nIf the light curve continues to decay with a power-law decay index of\n3.32, the count rate at T+24 hours will be 1.8 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/00021728.\nThe results of the full analysis of the XRT observations are available\nat https://www.swift.ac.uk/ToO_GRBs/00021728.\n\nThis circular is an official product of the Swift-XRT team.\n\n",
  "eventId": "GRB 241105A",
  "subject": "GRB 241105A: Swift-XRT afterglow detection",
  "submittedHow": "email",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "createdOn": 1730894171079
}