Telescope array

The Big Picture: Rudnick helps lead effort that reveals the stormy weather in galaxy clusters

Professor Emeritus Lawrence Rudnick of the School of Physics and Astronomy led the Technical Working Group of the MeerKAT Galaxy Cluster Legacy Survey (MGCLS).

MeerKAT is a telescope array in South Africa that can study emission from electrons moving at near the speed of light, that is, at relativistic speeds. These relativistic electrons, much like water droplets suspended in foggy air, reveal the otherwise invisible motions of hot gas in the massive structures of clusters of galaxies. Radio emission from the sprinkling of relativistic electrons in this plasma can uncover the dramatic storms in clusters, stirred up when clusters collide with each other, or when jets of material spew out of supermassive black holes in the centers of galaxies.

“With the spectacular new capabilities of the MeerKAT telescope, we were able to lift the veil on processes in clusters of galaxies that were only hinted at before,” Rudnick said. “Our common reaction was ‘Oh! So that's what it really looks like!’”

The collaboration recently published a paper which presents more than 50 newly discovered patches of cluster-related emission. Some of them are explainable with our current understanding while others remain a mystery, awaiting advances in the study of the physical behavior of cluster plasmas. 

A number of additional studies delving more deeply into some of the initial discoveries are already underway by members of the collaboration. Beyond that, the richness of the science resulting from the MGCLS is expected to grow over the coming years, as astronomers from around the world download the data from the MeerKAT archive, and probe it to answer their own questions.“One of the most exciting things for me was seeing a whole new, talented generation of astronomers in South Africa who are advancing the science challenges with which we've struggled for a very long time,” Rudnick said.

The MeerKAT telescope is operated by the South African Radio Astronomy Observatory, which is a facility of the National Research Foundation, an agency of the Department of Science and Innovation. Partial support for Rudnick's efforts is provided by the U.S. National Science Foundation to the University of Minnesota.

A team of 40 South African and international scientists was involved in the detailed analysis that is presented in the paper and associated data release. They represent 19 institutions, including the University of KwaZulu-Natal, Rhodes University, South African Radio Astronomy Observatory, University of the Witwatersrand, University of Pretoria, University of Cape Town, North-West University, University of the Western Cape, African Institute for Mathematical Sciences, Inter-University Institute for Data Intensive Astronomy; U.S. National Radio Astronomy Observatory, University of Minnesota, Italian National Institute for Astrophysics, York University, University of Hamburg, University of Nigeria, U.S. Naval Research Laboratory, University of Bonn, Sapienza University of Rome.