Astronomers Detect ‘Megamaser’ Blasting Through Space
When we talk about astronomers spotting something in the far-off corners of the cosmos, it’s usually a galaxy, a star, or some other celestial object. Not this time. A team from South Africa has discovered an ultra-powerful radio-wave laser, a phenomenon known as a megamaser. At more than five billion light years away, this is the most distant megamaser ever seen.
Lasers have been a common technology on Earth for decades, but the “laser” spotted by Marcin Glowacki and his team is on a completely different scale than anything we’ve seen in our neck of the universe. The observation was made with the delightfully named MeerKAT radio telescope in South Africa. This marks the first megamaser detection for this instrument. It’s also the most distant seen by any telescope to date. Researchers named the megamaser “Nkalakatha,” which is an is a Zulu word meaning “big boss.”
Megamasers like this one are a product of galaxy collisions. When two galaxies smack into each other, their respective gas envelopes can become ultra-dense and stimulate hydroxyl molecules, consisting of one atom of oxygen and one atom of hydrogen. They release that energy in the form of radio signals. A maser is similar to a laser, but it’s composed of radio frequencies. Normally, these frequencies would not be visible in MeerKAT, but the expansion of the universe stretched it to a longer wavelength that is within the range of MeerKAT’s dishes.
These radio-frequency beams are like signposts that can point astronomers in the direction of galactic collisions. Many scientists believe that our own Milky Way galaxy is destined to collide with Andromeda. When that happens, the event will most likely produce a megamaser that will be visible if anyone is looking in our direction a few billion years in the future.
The MeerKAT telescope is located in the Karoo region of South Africa and consists of 64 radio dishes. It began operating in 2018. The Nkalakatha detection came from just a single night of observation. The project is working toward a 3,000-hour survey known as LADUMA (Looking at the Distant Universe with the Meerkat Array). Megamasers are just one of many phenomena the team could spot in the future. This is also just one small part of a planned world-spanning radio observatory known as the Square Kilometer Array with telescopes in South Africa and Australia. It will eventually feature thousands of dishes.