Progentiors of GRBs: Massive Stars

Largest Explosions in the Universe May Come from the Death of
Massive Stars

Movie: A fading source...
Caption:
A fading source observed over the span of 9 months
with the W. M. Keck 10-meter Telescope in Mauna Kea, Hawaii. Darker
colors correspond to brighter objects. The so-called transient
afterglow of GRB 980326 (at the center of each image) clearly faded in
the first month after the burst. The object at the center image was
originally interpreted as the host galaxy. But a very long exposure
in December (notice how much clearer star "f" gets) revealed that the
"galaxy" disappeared. Not likely! Instead, the object at the middle
picture is now argued by Bloom et al. in Nature to be the
underlying supernova accompanying the gamma-ray burst. The size of
these images on the sky is about the size of a postage stamp as seen
across a football field.