A refined position catalogue of the Swift XRT afterglows
/ Authors
A. Moretti, M. Perri, M. Capalbi, L. Angelini, J. Hill, S. Campana, D. Burrows, J. Osborne, G. Tagliaferri, G. Cusumano
and 15 more authors
P. Giommi, P. Romano, T. Mineo, J. Kennea, D. Morris, J. Nousek, C. Pagani, J. Racusin, A. Abbey, A. Beardmore, O. Godet, M. Goad, K. Page, A. Wells, G. Chincarini
/ Abstract
Received ; accepted Abstract. We present a catalogue of refined positions of 68 gamma ray bur st (GRB) afterglows observed by the Swift X-ray Telescope (XRT) from the launch up to 2005 Oct 16. This is a result of the refinement of the XRT boresight calibration. We tested this correction by means of a systematic study of a large sample of X-ray sources observed by XRT with well established optical counterparts. We found that we can reduce the systematic error radius of the measurements by a factor of two, from 6.5 '' to 3.2 '' (90% of confidence). We corrected all the positions of the aft erglows observed by XRT in the first 11 months of the Swift mission. This is particularly important for the 37 X-ray aft erglows without optical counterpart. Optical follow-up of dark GRBs, in fact, will be more effi cient with the use of the more accurate XRT positions.
Journal: Astronomy and Astrophysics