GCN Circular 6065
G. Vianello (INAF, IASF-Milano & Univ. dell'Insubria), A. Tiengo, S. Mereghetti (INAF, IASF-Milano) report: We discovered a faint dust scattering halo in the Swift XRT Photon Counting mode data of GRB 070129. The halo consists of a partial ring of radius ~2 arcmin located to the North-West of the GRB afterglow position. Analysis of the dynamical image (see Tiengo & Mereghetti 2006 A&A 449, 203) covering the period from T0+4700s to T0+7300s (where T0 is the BAT trigger time, as reported in GCN 6053) indicates that the halo is expanding and leads to an estimate of ~300 pc for the distance of the dust layer responsible for the scattering. Dust maps (Schlegel, Finkbeiner, & Davis 1998, ApJ, 500, 525) show a diffuse structure in the direction indicated by the partial ring, and a total Galactic extinction of A_v~0.4.