{
  "bibcode": "2019GCN.23941....1B",
  "body": "D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), J.P.\nOsborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U.\nLeicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'Ai\n(INAF-IASFPA) and P.A. Evans (U. Leicester) report on behalf of the\nSwift-XRT team:\n\nSwift-XRT has performed follow-up observations of the MAXI-detected\nburst GRB 190306A (Shidatsu et al. GCN Circ. 23937) in a series of\nobservations tiled on the sky. The total exposure time is 1.2 ks,\ndistributed over 7 tiles; the maximum exposure at a single sky location\nwas 379 s. The data were collected between T0+24.2 ks and T0+25.6 ks,\nand are entirely in Photon Counting (PC) mode. \n\nNo uncatalogued X-ray sources have been detected. The 3-sigma upper\nlimit in the field (not including the regions where the tiles overlap)\nranges from ~0.05 to ~0.15 ct s^-1, corresponding to a 0.3-10 keV\nobserved flux of 1.8e-12 to 6.1e-12 erg cm^-2 s^-1 (assuming a typical\nGRB spectrum).\n\nA previously-catalogued X-ray source has been detected, however because\nit is a catalogued object it is unlikely to be the afterglow.\n\nThe results of the XRT-team automatic analysis of the tiled XRT\nobservations, including a position-specific upper limit calculator, are\navailable at http://www.swift.ac.uk/xrt_products/TILED_GRB00078.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 23941,
  "createdOn": 1551980335000,
  "email": "valerio.delia@ssdc.asi.it",
  "subject": "GRB 190306A: Swift-XRT observations",
  "submitter": "Valerio D'Elia at ASDC  <valerio.delia@ssdc.asi.it>",
  "eventId": "GRB 190306A"
}