{
  "bibcode": "2015GCN.17405....1S",
  "body": "B. Sbarufatti (INAF-OAB/PSU), F. E. Marshall (NASA/GSFC), A. Maselli \n(INAF-IASFPA), A. Melandri (INAF-OAB),\tV. Mangano (PSU), M.C. Stroh\n(PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U.\nLeicester), C. Pagani (U. Leicester) and P.A. Evans (U. Leicester)\nreport on behalf of the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the\nFermi/LAT-detected burst GRB 150202B (Axelsson et al. GCN Circ. 17385)\nin a series of observations tiled on the sky. The total exposure time\nis 4.2 ks, distributed over 2 tiles; the maximum exposure at a single\nsky location was 4.7 ks. The data were collected between T0+95.4 ks and\nT0+107.3 ks, and are entirely in Photon Counting (PC) mode. \n\nFour uncatalogued X-ray sources have been detected, however none of\nthem is above the RASS limit or shows definitive signs of fading.\nTherefore, at the present time we cannot identify which, if any, is the\nafterglow. Details of these sources are given below:\n\nSource 1:\n  RA (J2000.0):  86.9565  =  05:47:49.57\n  Dec (J2000.0): +58.8301  =  +58:49:48.2\n  Error: 4.1 arcsec (radius, 90% conf.)\n  Count-rate: 0.0183 +/- 0.0030 ct s^-1\n  Flux: (6.1 +/- 1.0)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nSource 2:\n  RA (J2000.0):  86.5922  =  05:46:22.14\n  Dec (J2000.0): +58.9223  =  +58:55:20.5\n  Error: 5.7 arcsec (radius, 90% conf.)\n  Count-rate: (5.9 +/- 1.9) -3 ct s^-1\n  Flux: (3.2 +/- 1.0)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nSource 3:\n  RA (J2000.0):  86.7927  =  05:47:10.25\n  Dec (J2000.0): +58.7852  =  +58:47:06.8\n  Error: 6.4 arcsec (radius, 90% conf.)\n  Count-rate: (4.0 +/- 1.7) -3 ct s^-1\n  Flux: (1.60 +/- 0.67)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nSource 4:\n  RA (J2000.0):  86.8219  =  05:47:17.25\n  Dec (J2000.0): +58.9746  =  +58:58:28.7\n  Error: 5.5 arcsec (radius, 90% conf.)\n  Count-rate: (3.03 +/- 0.99) -3 ct s^-1\n  Flux: (6.5 +/- 2.1)e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\nSources 3 and 4 are positionally coincident with stars from the USNO B1\ncatalogue.\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_GRB00039.\n\nThe UVOT observation covers sources 1 and 3 in the UVW1 filter. There\nis nothing at the position of source 1; source 3 is bright as expected\nfrom the catalogued source.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 17405,
  "createdOn": 1423078631000,
  "email": "boris.sbarufatti@brera.inaf.it",
  "subject": "GRB 150202B: Swift XRT/UVOT observations",
  "submitter": "Boris Sbarufatti at INAF-OAB/IASFPA  <boris.sbarufatti@brera.inaf.it>",
  "eventId": "GRB 150202B"
}