Gamma Ray Astronomy
Introduction
There is a band of this radiation coming from the plane of the Milky Way, in addition to specific objects like neutron stars, and there is also a source at the center of the Milky Way.
Probes
Their wavelengths are smaller than the atoms in a mirror so γ-rays cannot be focused by reflection. Modern satellites use scintillators which convert γ-rays into photons The first dedicated Gamma Ray satellite was COS-B launched in 1975 by ESA.
1991 Compton
Sources
- Milky Way
- Cosmic rays ploughing into gas clouds. Believed to be much of cosmic gamma-ray source, allowing information to be derived on cosmic rays.
- Some pulsars
- Some quasars
Gamma Ray Bursters
A research satellite first detected a burster in 1968, although they had been detected by the military just before and kept secret. They are high-energy fluxes lasting several seconds - the flux detected is greater than any other object outside the Solar system.
Gamma-ray outbursts are distributed randomly across the sky and in 1997 were shown, by analysis of the all-sky map of bursts produced by the Compton Gamma-Ray Observatory and comparison with optically identified sources, to lie at distances of billions of light years.
Several thousand gamma-ray bursts have been detected.