Abstract:
We present a wide data set of gamma-ray, X-ray, UV/Opt/IR (UVOIR), and radio observations
of the Swift GRB100814A. At the end of the slow decline phase of the X-ray and optical
afterglow, this burst shows a sudden and prominent rebrightening in the optical band only,
followed by a fast decay in both bands. The optical rebrightening also shows chromatic
evolution. Such a puzzling behaviour cannot be explained by a single component model. We
discuss other possible interpretations, and we find that a model that incorporates a long-lived
reverse shock and forward shock fits the temporal and spectral properties of GRB100814 the
best.
