{
  "bibcode": "2019GCN.24404....1K",
  "body": "A. Keivani (Columbia U.), D. B. Fox (PSU), P. A. Evans (U. Leicester), J.\nA. Kennea (PSU), M. Santander (U. Alabama), & F. Krauss (GRAPPA/API,\nUniversity of Amsterdam) report:\n\n\nThe Neil Gehrels Swift Observatory observed the field of the IceCube EHE\nastrophysical neutrino candidate event IceCube-190503A (revision 1,\nhttps://gcn.gsfc.nasa.gov/gcn3/24378.gcn3) beginning May 3, 20:14:26 UT\n(2.85 hours after the neutrino arrival time).\n\nSwift utilized its onboard 19-point tiling pattern to cover a region\ncentered on R.A., Dec. (J2000) = 120.28d, +6.35d, with a radius of\napproximately 0.8 deg; estimated 90%-containment radii for this event are\n0.57 deg  to 0.77 deg depending on position angle. Swift-XRT collected ~800\ns per field of PC mode data per tile between 20:17:30 UT on 3 May and\n10:51:09 UT on 4 May. Data have been reduced using the analysis approach\nand software routines of Evans et al. 2014 (ApJS, 210, 8).\n\nSeveral X-ray sources are detected in these observations, most of which are\npreviously uncataloged and relatively low in flux, consistent with\nexpectations for serendipitous (unrelated) sources over a region of this\nextent. A few sources with a false positive rate of ~1% look like real\nX-ray sources. However, none of them look promising to be IceCube-190503A\ncounterparts due to their low flux and lack of variability.\n\nExcluding identified sources, the 3-sigma upper limit on the count rate of\nany point-like counterpart over the rest of the tiled region is 0.01 ct\ns^-1, which corresponds to a 0.3-10 keV flux of 4.0e-13 erg cm^-2 s^-1 for\na typical AGN spectrum (nH=3e20 cm^-2, Gamma=1.7).\n\nCoordinates and count rates for the X-ray sources are provided below. \n\nSource, RA, Dec, Error_90 (arcsec), XRT count rate (ct s^-1)\n\n-------------------------------------------------------------------------------------------------------------\n\n#1: 120.75962d, 7.01880d, 11.2, 1.0 (+0.5, -0.4) e-2\n\n-------------------------------------------------------------------------------------------------------------\n\n#2: 120.56238d, 6.63466d, 5.2, --\n\n-------------------------------------------------------------------------------------------------------------\n\n#3: 119.80197d, 7.11136d, 6.7, 1.1 (+0.6, -0.4) e-2\n\n-------------------------------------------------------------------------------------------------------------\n\n#4: 120.49133d, 6.05997d, 6.7, 9 (+6, -4) e-3\n\n-------------------------------------------------------------------------------------------------------------\n\n#5: 119.81789d, 6.45455d, 6.3, 1.0 (+0.5, -0.4) e-2\n\n-------------------------------------------------------------------------------------------------------------\n\n#6: 120.14345d, 6.13111d, 7.8, 4.6 (+4.4, -2.7) e-3",
  "circularId": 24404,
  "createdOn": 1557140393000,
  "email": "azadeh.keivani@columbia.edu",
  "subject": "IceCube-190503A: Swift-XRT Follow-up Observations",
  "submitter": "Azadeh Keivani at Columbia U  <azadeh.keivani@columbia.edu>",
  "eventId": "IceCube-190503A"
}