{
  "body": "D.N. Burrows (PSU), J. D. Gropp (PSU), S. Dichiara (PSU), K.L. Page (U.\nLeicester), A.P. Beardmore (U. Leicester), B. Sbarufatti (INAF-OAB), C.\nSalvaggio (INAF-OAB), M. Ferro (INAF-OAB) and P.A. Evans (U. Leicester)\nreports on behalf of the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the Fermi/GBM,\nSwift/BAT-GUANO and Astrosat/CZTI detected burst GRB 240727B (Fletcher\net al. 2024, GCN 36949; Ronchini et al. 2024, GCN 36945; Waratkar et\nal. 2024, GCN 36943),  collecting 4.9 ks of Photon Counting (PC) mode\ndata between T0+33.5 ks and T0+52.2 ks. \n\nNo X-ray sources have been detected within 296 arcsec of the\nSwift/BAT-GUANO position. The 3-sigma upper limit in the field is 0.003\nct  s^-1, corresponding to a 0.3-10 keV observed flux of 1.0e-13 erg\ncm^-2 s^-1 (assuming a typical GRB spectrum).\n\nThree uncatalogued sources were detected too far from the GRB position\nto be likely afterglow candidates.\n\nThe results of the XRT-team automatic analysis of the XRT observations,\nincluding a position-specific upper limit calculator, are available at\nhttps://www.swift.ac.uk/ToO_GRBs/00021701.\n\nThis circular is an official product of the Swift-XRT team.\n\n",
  "bibcode": "2024GCN.36970....1B",
  "circularId": 36970,
  "createdOn": 1722243031741,
  "eventId": "GRB 240727B",
  "submittedHow": "email",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "subject": "GRB 240727B: Swift-XRT observations"
}