10 DICEMBRE 2019 ore 11:00

The flickering nuclear activity of Fornax A

Dr. Filippo Maccagni (INAF-OAC, Italia)
The flickering nuclear activity of Fornax A

No consensus has yet been reached on how galaxy interactions and AGN regulate the formation of early-type galaxies. The study of the all phases of the circum-nuclear interstellar medium can be used to trace the interaction events that formed a galaxy as well as the interplay between the AGN and the gaseous ISM. Fornax A is the third nearby radio AGN and it is hosted by an early-type galaxy with a rich history of interaction events. In this talk, I will show new MeerKAT L-band and SRT C-band observations of Fornax A. These observations, together with broad-band observations between 84 MHz and 217 GHz, have been critical in unlocking the history of the nuclear activity of this source, revealing its rapid flickering (~10 Myr). In the centre (<30 kpc), we have detected, for the very first time, 10^8 Msun of HI gas, distributed in several non-rotating clouds (probably the remnant of a past merger). In the innermost regions (r<6 kpc), clouds of HI, molecular and ionised hydrogen do not follow the regular rotation of the stellar body. In this talk, I will show how the kinematics and physical conditions of all phases of the circum-nuclear gas allow us to study the impact of the mechanical and radiative energy ejected from the AGN onto the ISM.

Image Credits: Dane Kleiner, Filippo Maccagni