The Swift view of GRB 060614

Abstract

GRB 060614 is a remarkable nearby GRB (z=0.125) observed by Swift. It has puzzling properties, which challenge current progenitor models: the lack of any bright supernova down to very strict limits and the vanishing spectral lags are typical of short GRBs, strikingly at odds with the long (102 s) duration of this event. However, the burst presents optical, UV and X-ray afterglows in remarkable agreement with standard jetted fireball models. In particular, spectral analysis of BAT and XRT data during the overlap time interval and after shows that the peak energy of the burst decays and crosses the XRT energy band within 500 s from the trigger. The afterglow shows a jet break simultaneously detected in optical, UV and X-rays. Moreover, the UVOT light curves possibly show evidence of the passage of the injection frequency across the optical band between 10 and 30 ks from the trigger. © 2008 American Institute of Physics.