Scientists in Okanagan Valley detect radio bursts from distant galaxy

Postado Janeiro 12, 2019

Several dozen FRBs have been recorded over the last decade, but CHIME's observations mark just the second time a repeating signal has been documented.

Fast Radio Bursts (FRBs) are very energetic, fleeting radio signals (they only last a few milliseconds), which are supposed to come from deep space. Incredibly, these radio waves originate from distant galaxies, travelling at high energies through the cosmos for literally billions of years.

Before CHIME began to gather data, some scientists wondered if the range of radio frequencies the telescope had been created to detect would be too low to pick up fast radio bursts.

"Fast radio bursts are exceedingly bright given their short duration and origin at great distances, and we haven't identified a possible natural source with any confidence", said Loeb in a statement after the publication of a previous paper in the Astrophysical Journal Letters.

These discoveries are among the first, eagerly awaited results from the Canadian Hydrogen Intensity Mapping Experiment (CHIME), a revolutionary radio telescope inaugurated in late 2017 by a collaboration of scientists that includes MIT's Kiyoshi Masui, an assistant professor of physics, and Juan Mena Parra, a Kavli postdoc. The source is from something with an extremely powerful magnetic field that produces a signal along the radio frequency band. But these were found in the band between 400 and 800 MHz.

Before CHIME, the majority of FRBs detected had been found at frequencies close to 1,400 megahertz.

"Different emission mechanisms expect that FRBs will be emitted within a certain range of radio frequencies, much like a light bulb can not emit X-rays or a microwave oven can not emit ultraviolet light", Tendulkar told Gizmodo. Fast radio bursts might actually be common - it's just that we're only just noticing them.

However, Tendulkar said it was extremely unlikely the waves were caused by intelligent life.

The new FRBs are are also at unusually low radio frequencies. The previous record of lowest-frequency FRB was of 700 megahertz.

It's still not clear whether the two repeaters represent a distinct class of objects from those that produce a single burst. What's more interesting is that one of the FRBs recorded by CHIME was repeating in nature and is claimed to have repeated six times from the same location. The source is estimated to be about 1.6 billion light years away, so seeing any details of what's going on is not going to be easy in any case.

Since FRBs occur so quickly, studying them and identifying the source is hard.

As for the mystery behind the FRBs - and especially the repeating ones - the Canadian team hopes that with CHIME now at full capacity, more of these repeaters will reveal themselves. Thousands could even discreetly reach us each day. The detection of these repeated signals could nevertheless help us to see a little more clearly. While it was waiting to come fully online, it picked up these 13 FRBs. That tells us something about the environments and the sources.

Artist's impression of the active galactic nucleus shows the supermassive black hole at the center of the accretion disk sending a narrow high-energy jet of matter into space, perpendicular to the disc in this image by Science Communication Lab in Kiel Germany, released on July 12, 2018.