Breaking News – Rhodes University researchers help release important data to change the future of space exploration


Two giant radiogalaxies (over a million light years from end to end) at the center of a large cluster of galaxies in the Abell 194 cluster, revealing the presence of relatively narrow magnetic filaments in the region, as well as complex interactions between the radio emission of the two galaxies. The MeerKAT radio image is shown in orange, with an optical image dominated by normal galaxies shown in white. Adapted from K. Knowles et al., “The MeerKAT Galaxy Cluster Legacy Survey. I. Survey Overview and Highlights ”(Astronomy & Astrophysics, in press). Image credit: SARAO, SDSS.

An international team, led by Rhodes University researcher Dr Kenda Knowles, has just announced a comprehensive review paper for the MeerKAT Galaxy Cluster Legacy Survey (MGCLS), accompanied by the public release of a vast mine of data that astronomers around the world can use. to answer a variety of difficult questions relating to the formation and evolution of galaxies in the universe.

The paper, “The MeerKAT Galaxy Cluster Legacy Investigation. I. Survey overview and highlights ”, which has been accepted for publication in the Astronomy & Astrophysics journal, presents exciting and innovative results.

“I am very excited to see the impact MeerKAT can have in the global astronomical space and look forward to seeing where the beautiful data takes us to better understand the many different components of our Universe,” said Dr Knowles, who is the main author of the paper. “The complexity that is revealed in the structures of radiogalaxies, and how common this complexity appears to be, is very exciting.”

Rhodes University researcher Dr Mpati Ramatsoku, who also contributed to the article, was also impressed by the “immense number of completely new and complex galaxy structures that have been revealed” by the data and how ‘survey “opens up a new perspective on how galaxies form, live and evolve.”

Using the MeerKAT telescope from the South African Radio Astronomy Observatory, located in the Karoo region of the Northern Cape Province, this first observatory-led survey demonstrates MeerKAT’s exceptional strengths in producing highly detailed and sensitive images of radio broadcast from 115 galaxy clusters. The observations, representing approximately 1,000 telescope hours, were taken the year after MeerKAT was launched in 2018.

More than two years of work followed converting raw data into radio images, using powerful computers, and performing scientific analyzes on a variety of topics.

“The Rhodes Center for Radio Astronomical Techniques and Technologies has been immensely supportive and provided all the facilities that have enabled us to make important contributions to this work, ”explained Dr Ramatsoku.

The force of gravity has filled the expanding universe with objects spanning an astonishing range of sizes, from comets 10 km (one thirty thousandth of a light second) in diameter, to clusters of galaxies that can expand. over 10 million light years. .

These galaxy clusters are complex environments, harboring thousands of galaxies, magnetic fields and vast regions – millions of light years in diameter – of extremely hot gas (millions of degrees), electrons and protons. moving near the speed of light and dark. question. These “relativistic” electrons, spiraling around magnetic fields, produce the radio emission that MeerKAT can see. Thus, MeerKAT, particularly when adding information from optical, infrared and X-ray telescopes, is exceptionally well suited to study the interaction between these components which determine the evolution of clusters of galaxies, the largest structures of the universe held together by gravity.

We live in an ocean of air, but we cannot see it directly. However, if it is filled with smoke, dust or water droplets, we can suddenly see the gusts and eddies, whether it is a gentle breeze or an approaching tornado. Likewise, the motions of plasma radiating from X-rays in galaxy clusters are generally hidden from us. The radio emission from the sprinkling of relativistic electrons in this plasma can reveal the dramatic storms in clusters, triggered when clusters collide with each other, or when jets of matter shoot out from supermassive black holes in the sky. center of galaxies. The MGCLS article presents more than 50 new emission zones discovered. We can understand some of them, and others remain a mystery, pending progress in our understanding of the physical behavior of cluster plasmas.

Some examples are associated with the light emission of so-called “radiogalaxies”, fed by jets from supermassive black holes. Others are isolated features, illuminating winds and intergalactic shock waves in the surrounding plasma. Other types of science enriched by the MGCLS include the regulation of star formation in galaxies, the physical processes of jet interactions, the study of weaker cold hydrogen gas – the fuel of stars – in various environments, and yet unknown investigations to be facilitated by serendipity. discoveries.

The MGCLS produced detailed images of the extremely faint radio sky while monitoring a substantial volume of space. “This is what has already allowed us to accidentally discover rare types of galaxies, interactions and diffuse radio broadcast characteristics, many of which are very beautiful,” said Dr. Knowles. But this is only the beginning.

“MeerKAT is making massive contributions to radio astronomy, but we still have a long way to go. Data like this offers many possibilities for training the next generation of South African astronomers,” she said.

Several additional studies deepening some of the initial findings are already underway by members of the MGCLS team. Beyond that, the wealth of science resulting from the MGCLS is expected to grow over the next few years, as astronomers around the world download data from the SARAO MeerKAT archive and probe it to answer their questions.

The paper:

K. Knowles et al., “The MeerKAT Galaxy Cluster Legacy Investigation. I. Survey overview and highlights ”, accepted for publication in Astronomy & Astrophysics.

The collaboration :

MeerKAT was conceived, designed and built over 15 years through the dedicated efforts of hundreds of people in South African research organizations, industry, academia and government. About 100 of these colleagues who built, operated and maintained MeerKAT are co-authors of the MGCLS article.

A team of 40 South African and international scientists participated in the detailed analysis presented in the document and the publication of associated data. They represent 19 institutions, including 10 in South Africa: 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 of Mathematical Sciences, Interuniversity Institute for Data Intensive Astronomy; United States National Radio Astronomical Observatory, University of Minnesota, Italian National Institute of Astrophysics, University of York, University of Hamburg, University of Nigeria, United States Naval Research Laboratory, University of Bonn, Sapienza University of Rome.

The telescope and the observatory:

The MeerKAT telescope is operated by the South African Radio Astronomy Observatory, a facility of the National Research Foundation, an agency of the Department of Science and Innovation.

Source: Communications

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