Gravitational lensing in plasma enviroment

by Prof. G.S. Bisnovatyi-Kogan

Monday 23 Nov 2009, 16:00 → 17:00 Europe/Rome

Aula Conversi (Dipartimento di Fisica - Ed. G.Marconi)

Gravitational lensing is predicted by general relativity,and is found in observations. Weak lensing, and observational examples of lenses, as well as theory of strong lensing with relativistic rings, are considered. When a gravitating body is surrounded by a plasma, even the uniform one, the lensing angle depends on a frequency of the electromagnetic wave due to refraction properties, and the dispersion properties of the light propagation in plasma. We consider here the spectrometric properties of a gravitational lens in a plasma, and estimate the possibility of the observation of this effect by the planned Russian space project Radioastron. The comparison is done between the gravitational spectrometrical effect in the uniform plasma, and spectrometrical effects due to the plasma nonuniformity. --