South Africa’s MeerKAT radio telescope has helped a group of international astronomers to discover 49 new galaxies, in less than three hours.
The observations were made possible by the Inter-University Institute for Data Intensive Astronomy (IDIA), a partnership of three South African universities: University of Cape Town, University of the Western Cape and University of Pretoria.
The overarching goal of IDIA is to build within the South African university research community the capacity and expertise in data-intensive research, to enable global leadership on MeerKAT large survey science projects and large projects on other Square Kilometre Array (SKA) pathfinder telescopes.
MeerKAT, originally the Karoo Array Telescope, is a radio telescope inaugurated in 2018, consisting of 64 radio dishes that are 13.5m in diameter and spread over an area of 8km in the Northern Cape.
It is the most sensitive telescope of its kind in the world and is a precursor to the SKA radio telescope, to be built in SA and Australia.
The SKA will be the largest radio telescope ever built and will produce science that changes our understanding of the universe.
Dr Marcin Glowacki, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR) in Western Australia, led the research, which aimed to study the star-forming gas in a single radio galaxy.
Although the team didn’t find any star-forming gas in the galaxy they were studying, Dr Glowacki instead discovered other galaxies while inspecting the data.
In total, the gas of 49 galaxies was detected. Dr Glowacki says this was a great example of how fantastic an instrument like MeerKAT is for finding the star-forming gas in galaxies.
“I did not expect to find almost 50 new galaxies in such a short time,” he says. “By implementing different techniques for finding galaxies, which are used for other MeerKAT surveys, we were able to detect all of these galaxies and reveal their gas content.”
According to IDIA, the new galaxies have been informally nicknamed the 49ers – a reference to the 1849 California gold rush miners.
Dr Glowacki views the 49 new galaxies as valuable as gold nuggets in our night sky. Many galaxies are near each other, forming galaxy groups, with several identified in one observation.
Three galaxies, in particular, are directly connected by their gas, he notes.
“These three are particularly interesting, as by studying the galaxies at other wavelengths of light, we discovered the central galaxy is forming many stars. It is likely stealing the gas from its companion galaxies to fuel its star formation, which may lead the other two to become inactive.”
Professor Ed Elson, from the University of the Western Cape and a co-author of the paper, says: “This discovery highlights the raw power of the MeerKAT telescope as an imaging instrument. The methods we developed and implemented to study the 49ers will be useful for MeerKAT large science surveys and smaller observing campaigns such as ours.”
IDIA notes that the discovery was no accident. Recently, an ICRAR summer student, Jasmine White, working with Dr Glowacki, helped to find even more gas-rich galaxies in other short observations made by MeerKAT.
“We hope to continue our studies and share even more discoveries of new gas-rich galaxies with the wider community soon,” Dr Glowacki says.
Of late, the MeerKAT radio telescope has been used by scientists to make ground-breaking findings.
Using the instrument, in April 2022, a team of researchers discovered a powerful megamaser – a radio-wavelength laser indicative of colliding galaxies.
In February last year, a team of astronomers made use of the radio telescope to find the most detailed images of the largest cosmic shock wave visible from earth. These gigantic shock waves are much larger than our entire galaxy and form when clusters of galaxies collide in what are the most energetic events after the Big Bang.
In January last year, the South African Radio Astronomy Observatory released a new MeerKAT telescope image of the centre of our galaxy, showing radio emission from the region with unprecedented clarity and depth.
In December 2021, astronomers utilised the MeerKAT to discover a mysterious chain of hydrogen gas clouds the size of a massive galaxy.
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