| OSSE and BATSE observations continue to provide information
on such topics as the definition of the binary orbit, the strength of the
neutron star magnetic field, and the basic physics of accretion.
Gamma-Ray Bursts The final source in the anticenter image is that of a gamma-ray burst. Normally, BATSE provides the only information on bursts. Once in a while, however, one of the imaging instruments can see the high-energy tail of a gamma-ray burst and actually image the burst emission. This information is quite valuable, allowing for a better localization of the burst, |
which is important when searching for counterparts. Before the launch of Compton, the consensus of the astronomical community was that gamma-ray bursters must be a class of neutron star, born in the supernova explosions of dying massive stars that inhabit regions near the plane of our galaxy. BATSE was expected to reveal a clustering of burst directions near the galactic plane. Furthermore, the neutron stars were expected by some investigators to produce repeated burst performances. BATSE, which detects about one burst per day, has not confirmed this galactic disk hypothesis. Instead, the celestial distribution of more than 2300 BATSE burst localizations is completely uniform on | the sky. We now know that the bursts indeed emanate from far outside
our galaxy, at distances exceeding 1 billion light years.
These are just a few of the images of our universe that Compton has provided astronomers. There is much more to the gamma-ray sky than this. Enhanced emission from diffuse clouds of gas, supernova remnants, and nearby normal galaxies are also detectable. Such static images give a somewhat misleading impression - perhaps the most important characteristic of the universe seen by Compton is that it is dynamic and unpredictable. |
The center of our galaxy is populated by many low-energy, rapidly
changing gamma-ray sources. BATSE monitoring helps to unravel the mystery
of these sources.
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