Foto del docente

Daniele Dallacasa

Associate Professor

Department of Physics and Astronomy "Augusto Righi"

Academic discipline: FIS/05 Astronomy and Astrophysics


Keywords: Clusters of Galaxies Plasma Astrophysics Radio galaxies Radioastronomical techniques

- Field of research n. 1 -
Radio emission is a short-lived phenomenon (10^7-10^8 yr) if compared to the typical age of galaxies (10^10 yr). It is unclear what are the ingredients necessary to produce relativistic electrons and magnetic field then producing synchrotron radiation. Giver the relatively quick evolution of the properties of radio sources, very important information comes from the objects in which the radio emission is in its early phase, coming from a region close to the nucleus of the host galaxy, and with typical ages of the order of thousand years. The investigation of these young and then small objects is a very important subject in the study of the origin of the radiated energy and on the properties of the ambient medium where the radio plasma is expanding.
- Field of research n. 2-
Clusters of galaxies allow the investigation of a variety of astrophysical phenomena. Radio emission provides information on the nuclear activity of the galaxies within the cluster and allow the study of the interaction of the relativistic plasma with the hot ionized gas which is found in the intergalactic space and represents the main contribution to the visible mass of the cluster itself. Furthermore, the diffuse emission occasionally found, without any association with a given galaxy, provides very important information on the dynamical history of accretion of new galaxies to the cluster, as captured by gravitational potential well of the cluster.
- Field of research n. 3-
The radio emission comes from magnetized relativistic plasma produced in the nuclear region of the host galaxy and then accelerated to velocities close to the speed of light towards the interstellar medium and then of the intergalactic medium. The interaction with such ambient media affects the properties of the synchrotron emission and allows to derive information on the physical condition of both the relativistic plasma and ambient media themselves.