Page 36 - EngineerIT May 2022

SPACE SCIENCES

To look for hydrogen, the team large amounts of data. This was made possible by the Inter-University Institute for Data
looks for light with a wavelength of Intensive Astronomy (IDIA) research cloud computing facility. This facility exists to help
21cm that has been stretched to longer the South African research community do as much science as possible with the MeerKAT,
wavelengths by the expansion of the and with the upcoming Square Kilometre Array in the future. Indeed, it is one thing to
universe. However, light from other collect a lot of data, and another to work with it.
atoms and molecules is also present, Facilities like IDIA’s are imperative if astronomers are to do as much science as
and in their very first observation with possible with the MeerKAT and with the Square Kilometre Array in the future.
MeerKAT, the team detected bright Once the team knew it was a megamaser, they went on to look for its host galaxy.
emission from hydroxyl molecules that Where was the megamaser coming from? The patch of sky explored by the LADUMA
had been even more stretched from its team has been observed in X-rays, optical light and infra-red, so the team was able
original wavelength of 18cm. to easily identify the host galaxy. The team also knew that such a powerful, distant
Dr. Marcin Glowacki, previously megamaser needed a good nickname, and invited members of the public to offer
a researcher at the Inter-University suggestions. The winning suggestion was “Nkalakatha,” an isiZulu word that means
Institute for Data-Intensive Astronomy “big boss,” which was suggested by Zolile Tibane, a student from Johannesburg who is
(IDIA) and University of the Western studying computer science at the University of the Western Cape.
Cape, and now based at the Curtin The host galaxy of “Nkalakatha” is known to have a long tail on one side, visible in
University node of the International radio waves. It is about 58 thousand billion billion (58 followed by 21 zeros) kilometres
Centre for Radio Astronomy Research away, and the megamaser light was emitted about 5 billion years ago when the universe
(ICRAR), led the investigation. was only about two thirds of its current age. “We have already planned follow-up
He explains, “It’s impressive that observations of the megamaser, and as LADUMA progresses we will make many more
in a single night of observations with discoveries,” notes Dr. Glowacki.
MeerKAT, we already found a redshift This is the first time a megamaser has been detected at that distance from its
record-breaking megamaser. The full emission at 18cm wavelength. The authors of the study point out that it is not surprising
3000+ hour LADUMA survey will be the that they found such a bright megamaser, given how powerful the MeerKAT is, but the
most sensitive of its kind.” When they telescope is very new, so this find hopefully is one of many more to come. “MeerKAT will
saw this signal in the data coming from probably double the known number of these rare phenomena. Galaxies were thought to
the telescope, and confirmed that it was merge more often in the past, and the newly discovered OH megamasers will allow us to
coming from hydroxyl, the team realised test this hypothesis,” comments Prof. Darling.
that they had a megamaser on their Radio astronomy is entering a truly exciting time with the upcoming Square Kilometre
hands. Array and its pathfinder telescopes, including MeerKAT. Unplanned discoveries are
To make this discovery, the team had starting to emerge from the unprecedented amounts of data these instruments collect.
to run complex scientific algorithms on And with MeerKAT and IDIA, South Africa is right at the cutting-edge of astronomy. n

Artist’s impression of a hydroxyl maser. Inside a galaxy merger are hydroxyl
molecules, composed of one atom of hydrogen and one atom of oxygen. When
one molecule absorbs a photon at 18cm wavelength, it emits two photons of the
same wavelength. When molecular gas is very dense, typically when two galaxies
merge, this emission gets very bright and can be detected by radio telescopes such
as the MeerKAT. © IDIA/LADUMA using data from NASA/StSci/SKAO/MolView

EngineerIT | May 2022 | 34