Binary Active Galactic Nuclei Research Articles

A CdTe gamma-camera for the space observatory INTEGRAL: software charge-loss corrections

The IMAGER gamma-ray telescope on board INTEGRAL features a coded aperture and a two-layer detector. The first of these layers, ISGRI, is a 16 384 pixel CdTe gamma-camera which will operate in the 20 keV–1 MeV energy range. The spectral performances of ISGRI at energies greater than 50 keV are obtained using a software charge-loss correction based on pulse rise-time measurements. At high energy, the study of the Compton interactions between the two IMAGER layers should ensure a good background rejection. This device will provide unprecedented performances in this energy range: a spatial resolution of 4 mm, a spectral resolution better than 7% at 122 keV and a broad band sensitivity at 3σ of about 10 −6 cm −2 s −1 keV −1 at 100 keV for a 10 5 s observation. Galactic X-ray binary sources, supernovae and active galactic nuclei will be prime targets for ISGRI.

Astrophysics and underground physics

High-energy astrophysics is critically discussed, covering supernova explosions, single and binary neutron stars and active galactic nuclei as well as some acceleration mechanisms like homopolar induction (in a rotating magnetized conductor), radial boosting by strong magnetic waves, electric discharges in clumped accretion flows and the grindstone effect of plasma falling on a rotating magnet. It is not clear whether the highest particle energies in the Galaxy are achieved in single-step or in coherent multiple-step accelerations.