Scientists have uncovered a wild space phenomenon called a “megamaser,” a massively powerful radio-wave laser caused by the dense merging of two galaxies. Through South Africa’s MeerKAT radio telescope, the megamaser’s bright emission is detectable even five billion light-years away.
MeerKAT is the collective name for a group of 64 fully-equipped antennae that make up one radio telescope in an area encompassing about one square kilometer. Each receptor unit includes the 13.5-meter positionable dish as well as all the supporting hardware like receivers and digitizers. There is also a 3.8-meter sub-reflector. The antennae can be aimed in different directions depending on research goals.
Now, the telescope has made news for its discovery of a distant megamaser some 58 sextillion kilometers away—that’s 58 followed by 21 zeroes. This is the most distant megamaser ever discovered, and the light we observe today has been traveling for longer than Earth has even existed.
A maser is the technical term for a laser made of microwaves rather than lightwaves. Radio waves have the longest wavelength of all, with microwaves just below them in the electromagnetic spectrum. From there, the next category is infrared waves; it’s only after infrared that visible light—the “optical” waves—are visible to the human eye. (X-rays and gamma rays are the tiniest waves with the highest frequencies.)
In research published last month on the preprint server arXiv (meaning the work has not yet been peer-reviewed), a team of almost 100 scientists from around the world detail how they discovered the megamaser. The maser is made of microwaves, which are not inherently luminous, themselves, but their behavior stimulates and throws photons out of the area, which we are able to see after all—giving us a luminous maser. In this case, the surrounding galaxies are luminous too, which is why we can observe them at all.
The maser is produced by two merging galaxies, a process that generates particles called hydroxyls—made up of one hydrogen atom and one oxygen atom. The tiny particles react by absorbing and ejecting photons, a process that is densified and intensified by the sheer number of reacting particles inside the merge zone. This is the light that forms the maser.
“When galaxies collide, the gas they contain becomes extremely dense and can trigger concentrated beams of light to shoot out,” lead researcher Marcin Glowacki tells SciTechDaily. Glowacki (detecting light was his birthright with that name!) works for the International Centre for Radio Astronomy Research in Western Australia, a part of Curtin University in the Perth suburb of Bentley.
As it turns out, first time’s charm. MeerKAT is relatively new, and this megamaser was detected on night one of a planned 125-day observation cycle. It’s sort of like winning the lottery with the first ticket you ever bought. “It’s impressive that, with just a single night of observations, we’ve already found a record-breaking megamaser. It shows just how good the telescope is,” Glowacki says.
The large research team named the new maser Nkalakatha, which means “big boss” in the local native isiZulu language of this part of South Africa.