{
  "bibcode": "2006GCN..5737....1R",
  "body": "P. Romano, C. Guidorzi (Univ Bicocca & INAF-OAB), A. Moretti (INAF-OAB),\nK. L. Page, (U. Leicester) on behalf of the Swift-XRT team\n\nAnalysis of the Swift XRT observation of GRB 061019 in Photon Counting\n(PC) mode has revealed in the first three orbits a diffuse X-ray halo\ncentered around the afterglow location.\nThe halo has the form of a complete ring which increases in radius through\nthe observation and reached the distance of >=100 arcsec during the first\n~17ks after the trigger (T0).\nWe can exclude it is due to instrumental effects.\nDuring the observation, which started ~2800 seconds after the burst\ntrigger time, the observed halo follows the expected behaviour\nof a \"light-echo\" as X-rays are scattered by dust in our Galaxy.\n\nGRB 061019 is in the direction (Galactic) l = 181.74, b = 4.26 degrees, in\nwhich the density of the interstellar medium is quite high as testified by\nboth the neutral Hydrogen column density nH=4.8E21 cm-2 and the optical\nextinction E(B-V)=1.144 (A_B=4.939).",
  "circularId": 5737,
  "createdOn": 1161293372000,
  "email": "patrizia.romano@brera.inaf.it",
  "subject": "GRB 061019: dust-scattered X-ray halo detected in Swift/XRT",
  "submitter": "Pat Romano at OAB-Swift  <patrizia.romano@brera.inaf.it>",
  "eventId": "GRB 061019"
}