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Radio signals from space pulse for three seconds: scientists

A signal consisting of fast bursts of radio waves in an apparent pattern has been detected from deep space – and astronomers believe it could be used to measure the expansion of future universe.

This radio “heartbeat,” detected by a special radio telescope in British Columbia, is described in a new paper published Wednesday in the journal Nature, explaining that the phenomenon is called is a fast radio burst (FRB).

An FRB is a sudden burst of strong, consistent radio waves from space with no discernible source but detectable over great distances.

One of the things that makes this new signal stand out is that most FRBs only last a few milliseconds when they come to life. However, this new signal, labeled FRB 20191221A, can last up to three seconds at a time, during which time astronomers have observed it emit radio waves that repeat every 0.2 seconds in a clear pattern.

This is the longest-lasting FRB to date, about 1,000 times longer than the average FRB.

“There aren’t many things in the universe that emit strictly periodic signals,” says Daniele Michilli, a postdoc at MIT’s Kavli Institute for Astrophysics and Space Research and one of the study’s authors. know in a press release.

“Examples that we know of in our galaxy are radio pulsars and magnetos, which rotate and produce an emission beam similar to a lighthouse. And we think this new signal could be a magnetic field or a pulsar on the steroid.”

This particular FRB was first detected in December 2019. Michilli was a researcher at McGill University at the time, scanning incoming data from the Canadian Hydrogen Intensity Mapping Experiment (CHIME), a The radio telescope in BC is made up of four large reflectors.

He recognized it immediately when CHIME received a new signal about a potential FRB.

“It was unusual,” he explained. “Not only is it very long, lasting about three seconds, but it also has remarkably precise cyclic peaks that emit fractions of a second — boom, boom, boom — like a heartbeat. This is the first time the signal itself is periodic. “

That day began the in-depth analysis that led to the paper being released this week.

Michilli and a team of astronomers looked at the signal and found that it had similarities to emissions from radio pulses and magnetic fields – both specific types of neutron stars – in our galaxy. we.

However, FRB 20191221A is almost a million times brighter.

Their current theory is that this radio signal comes from a distant pulsar or radio magnetic field that normally emits waves of lower intensity and ejects this rare giant beam for unknown reasons in a window. three seconds that CHIME can catch.

“This discovery raises questions about what could be causing this extreme signal that we have not seen before, and how we can use this signal to study the universe,” said Michilli. speak. “Future telescopes promise to detect thousands of FRBs per month, and at that point we could find many more periodic signals.”

If future outbursts from FRB 20191221A can be caught by CHIME, it could help astronomers track the expansion rate of the universe, astronomers say.

CHIME’s unique configuration – unlike most telescopes, it is immobile and has high mapping rates due to its large, consistent field of view – makes it optimal for FRB exploration, along with the observation of hydrogen gas in distant galaxies. The FRB’s extremely short lifespan means that you have to be extremely lucky to point your telescope into the right part of the sky at the right time, unless you’re looking with CHIME.

The first FRB was discovered in 2007. But in CHIME’s first year of operation after opening in 2018, it discovered more than 500 new FRBs.

“CHIME has now detected many FRBs with different properties,” says Michilli. “We have seen some living inside very chaotic clouds, while others look like they are in a clean environment. From the properties of this new signal, we can say that around this source, there is a plasma cloud that must be extremely turbulent.”

By mid-2020, CHIME had detected more than 1,000 FRBs. Scientists hope that soon, we’ll be able to pinpoint not just where everything comes from, but all of what these deep space flashes can tell us about the universe. pillar.

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