{
  "bibcode": "2007GCN..6065....1V",
  "body": "G. Vianello (INAF, IASF-Milano & Univ. dell'Insubria), A. Tiengo, S. \nMereghetti (INAF, IASF-Milano) report:\n\nWe discovered a faint dust scattering halo in the Swift XRT Photon \nCounting mode data of GRB 070129. The halo consists of a partial ring of \nradius ~2 arcmin located to the North-West of the GRB afterglow position.\n\nAnalysis of the dynamical image (see Tiengo & Mereghetti 2006 A&A 449, \n203)  covering the period from T0+4700s to T0+7300s (where T0 is the BAT \ntrigger time, as reported in GCN 6053) indicates that the halo is \nexpanding and leads to an estimate of ~300 pc for the distance of the dust \nlayer responsible for the scattering.\n\nDust maps (Schlegel, Finkbeiner, & Davis 1998, ApJ, 500, 525) show a \ndiffuse structure in the direction indicated by the partial ring, and a \ntotal Galactic extinction of A_v~0.4.",
  "circularId": 6065,
  "createdOn": 1170253895000,
  "email": "sandro@iasf-milano.inaf.it",
  "subject": "GRB 070129: dust-scattered X-ray halo detected by Swift/XRT",
  "submitter": "Sandro Mereghetti at IASF/CNR  <sandro@iasf-milano.inaf.it>",
  "eventId": "GRB 070129"
}