Properties and evolution of clusters and groups of galaxies derived
from multi-wavelength observations:
- AGN feedback
- Interaction between thermal intra-cluster medium and relativistic plasma
- X-ray cavities and radio bubbles observed in cool core systems
- Non-thermal emission from galaxy clusters
- Radio mini-halos and reacceleration of relativistic particles
- Mass determination of galaxy clusters from X-rays
Main Collaborators:
- F. Brighenti (Dept. of Physics and Astronomy, University of Bologna)
- G. Brunetti (INAF-IRA Bologna)
- R. Cassano (INAF-IRA Bologna)
- L. David (SAO-CfA, USA)
- S. Ettori (INAF, Astronomical Observatory of Bologna)
- L. Feretti (INAF, IRA Bologna)
- F. Gastaldello (INAF-IASF Milano)
- G. Giovannini (Dept. of Physics and Astronomy, University of Bologna)
- M. Giroletti (INAF-IRA Bologna)
- B. McNamara (University of Waterloo, Canada)
- M. Meneghetti (INAF, Astronomical Observatory of Bologna)
- P. Nulsen (SAO-CfA, USA)
- S. Schindler (University of Innsbruck, Austria)
- E. O'Sullivan (SAO-CfA, USA)
- J. Vrtilek (SAO-CfA, USA)
PhD Thesis
The research program carried out during the PhD was focused on the
nature and origin of radio mini-halos , diffuse radio
sources observed at the centre of some clusters of galaxies with
cooling flow (CF). In particular, a theoretical model has been
developed in which mini-halos originate from synchrotron emission of
relic relativistic electrons reaccelerated by MHD turbulence via
Fermi-like processes, the necessary energetics being supplied by the
CF. MHD turbulence is assumed to be frozen into the thermal ICM and
thus amplified in the CF region. An important qualitative implication
of the model is that there must be a fine-tuning of the turbulent
energy in order for diffuse radio emission and CFs to co-exist in
galaxy clusters (Gitti,
Brunetti & Setti 2002, A&A, 386, 456). The model has been
successfully applied to two observed mini-halos, the Perseus cluster
and Abell 2626. With the aim to further explore the connection
between mini-halos, ICM and CFs, the observational properties of known
mini-halos have been discussed in relation with those of host
clusters, showing that the radio power of mini--halos increases with
the maximum power of CFs (Gitti et al. 2004, A&A, 417,
1). The results achieved during the PhD can be inserted in the
context of the study of the interaction between relativistic plasma
and thermal plasma in the intra-cluster medium (ICM), with particular
relevance for CF clusters.
Properties and evolution of clusters and groups of galaxies derived
from multi-wavelength observations:
