Radio Galaxies

Chairs: Emanuela Orrú (ASTRON) and Marek Jamrozy (Jagiellonian University)

Giant Radio Galaxies

Giant radio galaxies are believed to be formed from relativistic jets of matter and energy, emanating from the central regions of active galactic nuclei. Synchrotron radiation, often polarized, from the radio jets and lobes of these objects will be studied with LOFAR. The low-energy electrons responsible for the low-frequency emission can propagate large distances from their origins in the central core or lobe hot spots, and large radio cocoons are expected to surround many objects. Using high angular resolution observations with the full international LOFAR array should help us to learn more about the low-energy electron population in these objects, and hopefully to better understand the acceleration mechanisms which produce the relativistic electrons responsible for synchrotron emission. The high degrees of polarization of giant radio galaxies makes them ideal polarization calibrators for the observation of weaker sources.

Using the polarization properties of a sample of giant radio galaxies (i.e. sources with a physical size of about 1 Mpc) we probed intergalactic magnetic fields outside galaxy clusters. (Stuardi et al. 2020)

 

NGC 6251

Total power radio map of the giant radio galaxy NGC 6251. Contours: WSRT 327 MHz data with resolution of 55″x100″ (from Mack K.-H., et al. 1997); colours: LOFAR DR2 143 MHz data with resolution of 20″x20″. See Cantwell et al. (2020).

Radio galaxy rotation measures