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 wave-lengths of a few billionths to a few trillionths of a metre. Most people know of these ray’s medical applications – with their help, one can produce images of the interior of human bodies – 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.