SA’s MeerKAT makes discovery of astronomical proportions

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South Africa’s MeerKAT telescope is a precursor to the Square Kilometre Array. (Photo source: SARAO)
South Africa’s MeerKAT telescope is a precursor to the Square Kilometre Array. (Photo source: SARAO)

South Africa’s MeerKAT radio telescope has made yet another discovery, this time discovering a group of 20 galaxies.

This comes after the powerful telescope discovered two giant radio galaxies earlier this year.

In a statement yesterday, the South African Radio Astronomy Observatory (SARAO) says the large galaxy group is likely the most neutral hydrogen gas-rich group ever discovered.

In addition, SARAO notes it is the first time this group has been identified, despite residing in a well-studied area of the sky.

According to the radio astronomy body, the majority of galaxies in the Universe reside in groups. However, it is rare to detect a group with such a large number of group members with so much neutral hydrogen.

This, it says, suggests the group is still in the process of assembly, as it has not undergone evolutionary processes that would remove this gas from the galaxies.

Shilpa Ranchod, MSc student at the University of Pretoria and lead author of a paper detailing the discovery, says: “The distribution of neutral hydrogen gas in these galaxies has revealed interesting, disturbed morphologies, suggesting these galaxies are group members, and are being influenced by their cosmic neighbours in the group.

“For example, we found an interacting pair of galaxies that will potentially merge to form a new galaxy with a completely transformed appearance.”

A precursor to the Square Kilometre Array (SKA), South Africa’s MeerKAT telescope located in the Northern Cape was launched in 2018. It aims to answer fundamental astrophysical questions about the nature of objects in the Universe.

According to SARAO, construction of the highly-anticipated trans-continental SKA telescope is due to commence in SA and Australia in 2021 and continue until 2027. Science commissioning observations could begin as early as 2023, it notes.

SARAO indicates the galaxy group was discovered by the MeerKAT International Gigahertz Tiered Extragalactic Exploration (MIGHTEE)survey. It is one of the large survey projects in progress with the MeerKAT telescope and involves a team of South African and international astronomers.

Dr Natasha Maddox, research scientist at Ludwig Maximilians Universität in Munich and co-chair of the MIGHTEE working group, comments: “This galaxy group sits in an area of sky that has been studied with many other telescopes, but only with MeerKAT is the group structure revealed so clearly. Galaxy environment strongly affects how galaxies change and grow, and observations of neutral hydrogen with MeerKAT give us a new observational window into structures like this.”

According to Dr Bradley Frank, SARAO’s associate director of astronomy operations at the Inter-university Institute for Data Intensive Astronomy and co-chair of the MIGHTEE, the discovery really highlights that MeerKAT is an amazing instrument.

“MeerKAT is an important step in the direction of the SKA – providing us with a view to future SKA science projects and lessons on how to overcome the many technical challenges involved in realising the true scientific potential of SKA and SKA pathfinders.”

Dr Anastasia Ponomareva, researcher at the University of Oxford and co-author of the paper, adds: “This discovery shows that our MeerKAT observations caught a galaxy group in the early stages of its assembly, which is very uncommon. Therefore, this discovery is not only important per se, but will set new grounds for understanding how galaxies are assembled into groups and transformed by their environment.”

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