South Africa: South African Telescope Detects Record-Breaking Signal From the Early Universe

Astronomers using the MeerKAT radio telescope in South Africa have discovered the most distant hydroxyl megamaser ever detected, opening a new radio astronomy frontier. A hydroxyl megamaser is a natural space laser, and this one is located in a violently merging galaxy more than 8 billion light-years away.

We spoke to the astronomers, Thato Manamela, a postdoctoral researcher at the University of Pretoria, and Roger Deane, director of the Inter-University Institute for Data Intensive Astronomy and a professor at the universities of Cape Town and Pretoria, about their study.

What you've found has been described as a 'new frontier' in space research. Why is it extraordinary?

This discovery is extraordinary because of the record distance at which we've detected it, over eight billion light-years away. That places it deep into the early universe. This means that we aren't seeing the galaxy as it exists today. We are seeing it as it was 8 billion years ago. Since the Big Bang happened about 13.8 billion years ago, we are looking at a "toddler" version of the universe. At that stage where the maser signal was transmitted by the host galaxy, galaxies were much more "chaotic", they collided more often and were much more active than the stable, mature galaxies we see nearby today.

It gives us a rare glimpse of galaxy interactions and extreme star-forming environments when the cosmos was less than half its current age. Think of light like a letter in the mail. If a friend sends a letter from overseas, by the time you read it, the news is old. In space, light is the letter. The "news" from this galaxy took 8 billion years to reach us. We see the galaxy as a "toddler" even though, in its own time, it has already grown up or changed.

We detected this megamaser, which operates on a scale of power millions of times greater than a typical galactic maser. Both megamasers and gigamasers are cosmic radio lasers. While a megamaser is a million times more luminous than a standard maser found in the local universe, a gigamaser is a billion times more luminous, making it 1,000 times more powerful than a megamaser.

In just five hours of observing time we found a signal that typically requires hundreds of hours of observation, given its distance and rarity. But gravitational lensing boosted the signal enough to detect it. Additionally, while we were targeting neutral hydrogen, MeerKAT's wide bandwidth enabled the surprise discovery of the megamaser signal in the same data.

This rapid detection suggests that future surveys with MeerKAT and the upcoming SKA Observatory coul