(ORDO NEWS) — Powerful laser radiation with a radio wavelength has been detected at the greatest distance in deep space.
This is a type of massless space object called a megamaser, and its light traveled 5 billion light years to reach us on Earth.
Astronomers who discovered it with the MeerKAT radio telescope in South Africa named it Nkalakatha, an Izizulu word meaning “big boss”.
The discovery has been accepted into The Astrophysical Journal Letters and is available on the arXiv preprint server.
“It’s impressive that in just one night of observations we’ve already found a record megamaser,” said astronomer Marcin Glowacki of the Curtin University node of the International Center for Radio Astronomy Research (ICRAR) in Australia.
“It shows how good the telescope is.”
A maser is the microwave equivalent of a laser (light amplification by stimulated emission). Instead of emitting visible light, a maser emits microwaves and radio waves that are stimulated and amplified.
For an astrophysical maser, the processes that amplify light are cosmic; planets, comets, clouds and stars can create masers.
As you may have guessed, a megamaser is a maser with some serious power. As a rule, such emissions are produced by an object that, in some sense, is peddling; for example, active supermassive black holes can produce megamasers.
When data came in from the first night of the 3,000-hour study, Glowacki and team found the signature of a very specific type of megamaser, bright at wavelengths, enhanced by stimulated hydroxyl molecules made up of one hydrogen atom and one oxygen atom.
Hydroxyl megamasers have a known production mechanism. They are emitted by galaxies that are in the process of colliding with another galaxy or have recently collided with it, resulting in violent star formation.
The gravitational force from such a massive collision compresses the star-forming gas, causing it to break up into stars at great speed.
The source of the megamaser discovered by Glowacki and colleagues is just such a galaxy called WISEA J033046.26-275518.3 – now known as Nkalakatha.
“When two galaxies collide, such as the Milky Way and the Andromeda galaxy, beams of light emanate from the collision that are visible at cosmological distances,” says astrophysicist Jeremy Darling of the University of Colorado.
“Hydroxy megamasers act like bright lights that say there’s a galaxy collision going on here, creating new stars and feeding massive black holes.”
The MeerKAT study is not designed to search for megamasers. It’s called Looking at the Distant Universe with the Meerkat Array (LADUMA), and it’s looking for the 21-cm wave emitted by neutral hydrogen in the early universe, redshifted by the expansion of the universe.
The wavelength of the hydroxyl megamaser, however, is 18 centimeters; when it is overexposed, it is even longer, and this overexposed signal is within the range detectable by the telescope.
Since this region of the sky was already actively observed in other wavelength ranges, it was quite easy to track the signal to the host galaxy.
Nkalakatha is bright in infrared and has a long tail on one side that glows brightly in radio, likely as a result of gravitational interaction between the two merged galaxies.
The team has already planned follow-up observations of this amazing object and expects to find many more megamasers as the study continues.
“MeerKAT is likely to double the known number of these rare events,” Darling said. “In the past it was believed that galaxies merge more frequently, and the recently discovered hydroxyl megamasers will allow us to test this hypothesis.”
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