Huub Rottgering (Leiden University)

LOFAR and the origin and evolution of galaxies and clusters -- Huub Rottgering Colloquium

Marsfield Lecture Theatre

Abstract

LOFAR’s world-class observational capabilities will be used to survey the entire Northern low-frequency sky at a number of key frequencies. Studies of the most distant radio galaxies, clusters of galaxies and the cosmic star formation history and the exploration of new parameter space for serendipitous discovery were the four key topics that drove the areas, depths and frequency coverage of the
proposed surveys.

In this talk, I will first discuss the status of the LOFAR project and the many challenges that are being addressed to make deep low frequency images.

In the second part I will discuss in detail recent radio observations of clusters that provided important information on the impact of shocks and mergers on the general evolution of clusters. In the last years we have embarked on a large project to elucidate the relation of
diffuse radio sources in clusters and properties of the ICM.
Presented will be results from studies of individual clusters including the spectacular 'sausage' and 'toothbrush' clusters. These provide measurements of the properties of the shocks such as Mach numbers and magnetic field strengths. Also assisted by simulations, we then show how many parameters of merging clusters can be constrained
(mass ratio, impact parameter, orientation).

Finally, the first LOFAR observations on selected nearby clusters will presented.