Colloq Abstract - Dwarakanath
Sept. 13
11:00am Mountain
Dwarakanath, K.S. (RRI)
Diffuse Radio Emission in Galaxy Clusters
Abstract
Galaxy clusters are some of the largest gravitationally
bound structures in the Universe. Satellite observations
during the early 70's discovered diffuse X-ray emitting hot gas
in the clusters. Cluster-wide non-thermal radio emission
was also subsequently discovered in some of the X-ray bright clusters
and has been a topic of multi-wavelength studies ever since.
This radio emission, which is not associated with any of the cluster
galaxies, arises due to relativistic particles and
magnetic fields in the Intra Cluster Medium and is
extended over millions of light years, similar to the
extent of the hot and tenuous X-ray emitting gas
found in galaxy clusters. Such large scale radio emission has posed
challenges to its imaging and its understanding. The basic
issues concern the production and sustenance of relativistic
particles and magnetic fields over millions of light years.
One of the currently popular model invokes cluster mergers
to explain the existence of diffuse radio emission in clusters.
But, there are alternative scenarios.
Over the last five decades much progress has been made on both the
observational and theoretical fronts;
resolving some of the earlier issues, but, raising many new questions.
I will summarise the current status in this area of research and
highlight some of the outstanding problems. Improvements in modeling
and simulations and the emergence of next generation radio telescopes
like the MWA, LOFAR and the SKA are expected to play a significant
role in addressing some of these problems.
