1) A broad glowing arc of radiance, sometimes seen high in the
western sky at → twilight,
caused by the → scattering effect of
→ fine dust particles
suspended in the → upper atmosphere.
2) Lingering → radiation that remains after a violent
→ event such as a
→ gamma-ray burst. The afterglow of any gamma-ray burst
is caused by an event different from the original explosion, likely
by → shock waves colliding with the ambient medium.
Afterglows occur in a large range of → electromagnetic
→ after; → glow.