The optical afterglow of GRB 000911: Evidence for an associated supernova?

Abstract

We present photometric and spectroscopic observations of the late afterglow of GRB 000911, starting ∼1 day after the burst event and lasting ∼8 weeks. We detect a moderately significant re-brightening in the R, I and J lightcurves, associated with a sizable reddening of the spectrum. This can be explained through the presence of an underlying supernova, outshining the afterglow ∼30 days after the burst event. Alternative explanations are discussed.