{
  "bibcode": "2021GCN.29827....1K",
  "body": "J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), J.P. Osborne (U.\nLeicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), T.\nSbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), M.G. Bernardini\n(INAF-OAB), B. Sbarufatti (PSU) and P.A. Evans (U. Leicester) report on\nbehalf of the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the\nSwift/BAT-detected burst GRB 210413B (Swift/BAT did not successfully\ntrigger on GRB 210413B et al. GCN Circ. 29819), collecting 4.9 ks of\nPhoton Counting (PC) mode data between T0+185.0 ks and T0+206.7 ks. \n\nOne uncatalogued X-ray source has been detected consistent with being\nwithin 394 arcsec of the Swift/BAT position, it is below the RASS limit\nand shows no definitive signs of fading. Therefore, at the present time\nwe cannot confirm this as the afterglow. Details of this source are\ngiven below:\n\nSource 1:\n  RA (J2000.0):  182.5333  =  12:10:7.98\n  Dec (J2000.0): +56.0497  =  +56:02:59.0\n  Error: 5.7 arcsec (radius, 90% conf. [Enhanced position])\n  Count-rate: (4.5 +/- 1.2)e-3 ct s^-1\t \n  Distance: 309 arcsec from Swift/BAT position.\n  Flux: (1.42 +/- 0.39)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nThree uncatalogued sources were also detected too far from the GRB\nposition to 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/00021428.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 29827,
  "createdOn": 1618690026000,
  "email": "antonino.dai@inaf.it",
  "subject": "GRB 210413B: Swift-XRT observations",
  "submitter": "Antonino D'Ai at IASF-PA  <antonino.dai@inaf.it>",
  "eventId": "GRB 210413B"
}