Branch of physics devoted to the observation of X-rays reaching us from the depths of space. Such radiation is typically produced as the thermal radiation of matter at extremely high temperatures. An important example are the hot gases in the accretion disc of a black hole.
Highly energetic electromagnetic waves with frequencies between a few hundred Quadrillions and a few hundred Quintillions of oscillations per second, corresponding to wavelengths of a few billionths to a few trillionths of a metre. Most people know of these ray’s medical applications – with their help, images of the interior of human bodies can be taken – however, they are also used in (X-ray) astronomy.
Satellite project of the European space agency ESA. Launched in December 1999, XMM Newton is a space-based X-ray telescope; as such it is especially suited for research on the luminous phenomena associated with black holes.