The big accelerator in the sky

Article Abstract:

A source of high-energy gamma-rays, which astrophysicists designated 1E1740.7-2942, may also be producing radio waves and positrons. Since the 1970s researchers have been trying to identify the source of an intense outflow of positrons from the Galactic Center; positrons create gamma-ray energy by colliding with electrons, their antimatter opposites. The latest spectral data indicate that 1E1740.7-2942 is in the Milky Way Galaxy, is emitting radio waves and is more likely to be a neutron star or star-sized black hole than an extremely massive black hole.

Galactic center, Positron annihilation, Radio sources (Astronomy), Radio sources (Astronomical bodies)

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A needle in a cosmic haystack

Article Abstract:

There is evidence for two distinct populations among the persistent unidentified sources in the Galaxy. These are bright sources spread within the Galactic disk and a large number of fainter objects that seem to lie in the solar neighbourhood. New research has shown, without modelling, that the stable sources away from the Galactic plane are distinguished in spectral properties and intensity from the sources in the plane. This and earlier research provides strong evidence that the Gould belt is a significant birthplace of gamma-ray sources.

Galaxies, Galactic evolution

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Abandon all models

Article Abstract:

Donald Lamb and Bohdan Paczynski debated on the source of gamma-ray bursts (GRB) at the Museum of Natural History in Washington, DC, on Apr. 22, 1995. The debate was conducted in part to commemorate the great astronomical debate between Harlow Shapley and Heber D. Curtis on the nature of 'spiral nebulae' in Apr. 1920 at the same venue. Most astronomers believe that GRBs have a cosmological origin, but this has yet to be proven. There is a possibility that GRBs may be caused by a local population of sources.

Gamma rays

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