Afterglow
Credit:
Courtesy
BeppoSAX Team
This sequence of three false color X-ray pictures
from the
Italian/Dutch BeppoSAX satellite
follows the fading glow from
a gamma-ray burster.
This burster triggered orbiting gamma-ray observatories
on December 14, 1997
and within 6.5 hours the sensitive
X-ray cameras onboard BeppoSAX had been turned to
record the first image (left) of the afterglow.
Each image covers a field about the size of the full moon with the
position of the afterglow indicated by the white circle.
The first two pictures were taken 6 hours apart, while the final
picture was made 2 days after the gamma-ray burst.
Initiated by an unknown but immensely powerful explosive event,
gamma-ray bursts
are thought to be caused by blast waves
of particles moving at nearly the speed of light.
The expanding cosmic fireball produces seconds-long bursts of
gamma-rays and then as it slows and sweeps up surrounding material,
generates an afterglow visible for many days at X-ray, optical,
and radio energies.
Evidence indicates that this burst
originated at a distance
of 12 billion light-years requiring a fantastic and extreme energy source.
What could power a gamma-ray burst?