{
  "bibcode": "2016GCN.20125....1E",
  "body": "P.A. Evans (U. Leicester), J.A. Kennea (PSU), A. Keivani (PSU), D.B. Fox\n(PSU), G. Tesic (PSU), D.F. Cowen (PSU), J.P. Osborne (U. Leicester),\nM.W.E. Smith (JPL) and F.E. Marshall (GSFC) report on behalf of the\nSwift-IceCube collaboration:\n\nSwift has observed the field of the IceCube HESE event IceCube-161103\nutilising the on-board 19-point tiling pattern to cover a region centred\non RA,Dec (J2000) = (40.874,+12.616), with a radius of approximately 0.8 \ndegrees. Swift-XRT collected between 150 and 250 s of PC mode data per \ntile. The observations were taken between 13:58:30 and 18:55:15 UT on \n2016 November 3 (i.e. from 17.5 ks to 35.3.5 ks after the neutrino \ntrigger), and covered 2.1 square degrees.\n\nFour X-ray sources are detected in the observations. None of these are\nknown X-ray emitters, however all are faint, and well below the RASS \nlimits, therefore we do not consider any of them to be likely \ncounterparts to the IceCube trigger.\n\nThe 3-sigma upper limit on the count rate in the rest of the field \nranges is 0.03 ct s^-1, which corresponds to a 0.3-10 keV flux of \n1.2e-12 erg cm^-2 s^-1 for a typical AGN spectrum (NH=3e20 cm^-2, \nGamma=1.7). Overlaps between the different tiles accounts for 0.5 square \ndegrees: in these regions the 3-sigma upper limit is 0.02 ct\ns^-1, corresponding to 8.1e-13 erg cm^-2 s^-1.\n\nDetails of the four detected X-ray sources are below. All fluxes are\n0.3-10 keV and assume the same AGN spectrum as above.\n\nSource 1\n========\nRA:          02h 42m 42.34s = 40.6764d\nDec:         +12d 09' 40.1\" = 12.1611d\nError:       3.5 arcsec (90% confidence radius)\nCount rate:  (3.9 [+1.7, -1.3]) x 10^-2 ct s^-1\nFlux:        (1.6 [+0.7, -0.5]) x 10^-12 erg cm^-2 s^-1\n\n\nSource 2\n========\nRA:          02h 44m 51.43s = 41.2143d\nDec:         +12d 57' 23.3\" = 12.9565d\nError:       6.4 arcsec (90% confidence radius)\nCount rate:  (3.8 [+1.8, -1.4]) x 10^-2 ct s^-1\nFlux:        (1.5 [+0.7, -0.6]) x 10^-12 erg cm^-2 s^-1\n\nSource 3\n========\nRA:          02h 44m 51.43s = 41.6322d\nDec:         +12d 34' 09.1\" = 12.5692d\nError:       3.7 arcsec (90% confidence radius)\nCount rate:  (3.5 [+1.9, -1.4]) x 10^-2 ct s^-1\nFlux:        (1.4 [+0.7, -0.6]) x 10^-12 erg cm^-2 s^-1\n\nSource 4\n========\nRA:          02h 46m 07.42s = 41.5309d\nDec:         +12d 44' 11.3\" = 12.7365d\nError:       3.0 arcsec (90% confidence radius)\nCount rate:  (3.8 [+1.8, -1.4]) x 10^-2 ct s^-1\nFlux:        (1.5 [+0.7, -0.6]) x 10^-12 erg cm^-2 s^-1",
  "circularId": 20125,
  "createdOn": 1478268659000,
  "email": "pae9@leicester.ac.uk",
  "subject": "IceCube-161103: Swift-XRT observations",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>"
}