Composite image of Centaurus A. Two radio jets of plasma launched from the nuclear black hole are propagating in the intergalactic medium. Credits: ESO/WFI (visibile); MPIfR/ESO/APEX/A. Weiss et al. (microwave); NASA/CXC/CfA/R. Kraft et al. (X-ray) 

The Extragalactic Research Group in Torino focuses its activity on observational and theoretical aspects of Active Galactic Nuclei (AGN) and specifically of radio galaxies. AGN are very compact regions at the center of galaxies which emit a huge amount of energy from the accretion of gas and dust onto a massive black hole, with a mass from a million to 10 billion solar masses. In some cases, part of the energy produced by the accretion process is channeled in two relativistic jets of charged particles moving at a relativistic speed perpendicular to the disk. These jets emit mainly in the radio band and, in these cases, the host galaxies are defined “radio galaxies”.

Personnel

Barbara Balmaverde, Gianluigi Bodo, Alessandro Capetti, Maria Isabel Carnerero, Alessandro Paggi, Claudia M. Raiteri, Paola Rossi, Massimo Villata

Main Research Fields

• At the Observatory of Torino, we study radio galaxies with multi-wavelength data from all the bands of the electromagnetic spectrum, taking advantage of space and ground-based facilities, such as the Hubble Space Telescope (HST), Chandra (in X-ray), Very Large Telescope (VLA) in Chile o l’Atacama Large Millimeter Array (ALMA). The main goal is to investigate the origin of the different radio galaxy characteristics, the physical mechanism that power the observed emission and the impact that the energy released by the AGN has on the host galaxy and its environment (ref. Balmaverde, Capetti).
• Whether the jets are oriented along our direction of sight, the AGN is called a “blazar”. Its emission is relativistically beamed and it is highly variable in all bands. The WEBT collaboration (Whole Earth Blazar Telescope; https://www.oato.inaf.it/blazars/webt/ ), led by researcher of the Observatory of Torino, carries out observational campaign to monitor blazar’s variability, with the main goal to identify the physical mechanism that power the jet emissions (ref. Carnerero, Raiteri, Paggi, Villata).
• From a theoretical point of view, the radio jets are explored through multi-scale simulations of high energy astrophysical plasmas that try to reproduce the observed properties (ref. Bodo, Rossi).

Methods

• Analysis of multi-frequency data of the nuclei and jets of radio galaxies
• Monitoring of light curves of blazars
• multi-scale simulations of high energy astrophysical plasmas

Projects