Project Details
Projekt
Jet Feedback on Groups and Galaxy Clusters
Subject Area
Astrophysics and Astronomy
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 443220636
Galaxy formation is one of the most fascinating problems in modern-day astrophysics. In the standard model, galaxies form at the center of dark matter halos, but the halo mass and galaxy luminosity distributions differ significantly, implying that gas is less efficiently converted to stars towards the scale of galaxy groups and clusters. The interaction between cooling gas, subsequent star formation, and nuclear activity appears to be tightly linked in a self-regulating feedback loop that may explain this puzzle. The objective of this project is to investigate the active galactic nucleus (AGN) feedback loop, both from a theoretical and observational perspective. To achieve this, the project uses LOFAR data, as well as data from other radio telescopes, and cutting-edge zoom-in cosmological magneto-hydrodynamical simulations, which include cosmic ray and AGN jet physics for galaxy groups and clusters and evolve the Fokker-Planck equation for the momentum spectrum of relativistic electrons. These simulations aim to explore how jets transfer energy and momentum to the intracluster medium (ICM), thereby regulating cooling and star formation. We will compare observed and synthetic radio emissions to calibrate the feedback process in collaboration with our Mercator fellow Judith Croston. Seemingly unrelated to jet feedback at the centres of galaxy clusters, recent (low-frequency) radio observations show the emergence of a large population of giant radio galaxies (GRGs), which extend over more than 1 Mpc as projected on the sky. While the steep spectral indices suggest that GRGs represent an advanced evolutionary stage of typical radio galaxies, the physical processes responsible for their formation remain unclear. Improvements in observational population studies and cosmological simulations are required to elucidate their origin, which could be caused by (a combination of) jet power, environmental factors such as density and gas cooling time, and host galaxy characteristics. Thus, the morphological appearance of GRGs and radio galaxies could be intrinsically related to their ability to energetically couple to the surrounding gas in groups and clusters. The results from this project will provide large-scale constraints for small-scale relativistic jet models, which will be further developed in this proposed research unit in collaboration with our Mercator fellow Manel Perucho. Our main research questions are: 1.\ How does AGN jet feedback emerge over cosmic history and across different halos from groups to clusters? How is feedback energy transferred from the AGN jets to the cooling ICM and which observational signatures demonstrate this unambiguously? 2.\ What causes GRGs and which energy fraction can they afford for feedback so that they are still propagating Mpc distances?
DFG Programme
Research Units
Subproject of
FOR 5195:
Relativistic Jets in Active Galaxies
