{
  "bibcode": "2019GCN.24419....1E",
  "body": "Phil Evans (U. Leicester) and F.E. Marshall (NASA/GSFC)\nreport on behalf of the Swift team:\n\nSwift-XRT has performed follow-up observations of the AGILE-detected\nburst GRB 190501A (Ursi et al. GCN Circ. 24360), collecting 2.9 ks of\nPhoton Counting (PC) mode data between T0+146.7 ks and T0+157.7 ks.\nThe XRT field-of-view covers about 7% of the AGILE/GRID\n95%-confidence error region (Verrecchia et al. GCN Circ. 24363) and none of\nthe IPN 3-sigma error region (Hurley et al. GCN Circ. 24732).\n\nNo uncatalogued X-ray sources have been detected. The 3-sigma upper\nlimit in the field ranges from ~0.003 to ~0.004 ct s^-1, corresponding\nto a 0.3-10 keV observed flux of 1.2e-13 to 1.7e-13 erg cm^-2 s^-1\n(assuming a typical GRB spectrum).\n\nThree previously-catalogued X-ray sources have been detected, however\ntheir status as catalogued objects makes them unlikely to be the\nafterglow.\n\nThe results of the XRT-team automatic analysis of the XRT observations,\nincluding a position-specific upper limit calculator, are available at\nhttp://www.swift.ac.uk/ToO_GRBs/00020892.\n\nThe Swift/UVOT began settled observations of the field of GRB 190501A\n146672 s after the AGILE trigger.\nNo optical afterglow consistent with the AGILE/GRID position\nis detected in the initial UVOT exposures.\nThe UVOT images cover about 4% of the 95%-confidence\nAGILE/GRID error region and none of the IPN 3-sigma error region.\nPreliminary 3-sigma upper limits using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nwhite           147234       153893          933         >21.8\nv               147796       154103          761         >20.0\nu               146672       157636         1167         >20.7\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.03 in the direction of the burst\n(Schlegel et al. 1998).\n\nThis circular is an official product of the Swift team.",
  "circularId": 24419,
  "createdOn": 1557234639000,
  "email": "marshall@milkyway.gsfc.nasa.gov",
  "subject": "GRB 190501A: Swift XRT and UVOT Observations",
  "submitter": "Frank Marshall at Swift/UVOT  <marshall@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 190501A"
}