What is this mysterious radio eruption from deep space?

Which star object could have produced this signal? An international team of astronomers has discovered a very unusually fast radio eruption coming from space.

Radio outbursts are very intense and very short energy outbursts. They only last a few milliseconds. They are composed of radio waves that are more than a million times longer than waves in the visible domain (see diagram below). Rapid radio eruptions are among the most energetic cosmic events known. They were first discovered in 2007. But what causes them is still unknown today.

Here is the electromagnetic spectrum. To the left radio waves. In the middle the waves corresponding to the light visible to the human eye. Credit: CEA.

Also read: Strange radio waves coming from the center of our galaxy are confusing experts. A team of researchers from the University of Sydney reports the discovery of an unprecedented source of radio waves. Baptized ASKAP J173608.2−321635, this source would be located about 4 ° from the center of the Milky Way. Because it does not fit any known model of a variable radio source, it can fit a whole new class of star objects.

A rapidly repeating radio outbreak

Most radio eruptions come from other galaxies. They suddenly appear and then disappear. Which makes them very difficult to predict.

The radio eruption in question was first seen in 2019 by a Chinese radio telescope. The data pointed to the signal about 3 billion light-years away.

It was named FRB 190520B. Astronomers were able to observe it with another American radio telescope. They found that this signal repeated itself, unlike most other radio outbursts.

Between each very intense and fast signal, the FRB 190520B emits weaker. Its radio emission is therefore sustained … Astronomers believe it may be a signal from the explosion of a supernova. The dense material thrown out after the explosion would gradually disappear, which would lead to a reduction in the spread of the explosion signals. Thus, the repetition of a signal could be a characteristic signature of young radio outbursts.

radio outbreak

This table represents six bursts of radioburst FRB 20190520B that have occurred at different observation periods. There is a signal intensity peak for each of the six bursts. Credit: C.-H. Niu et al.

An “exotic” physique

This is not the first time that a repeated radio outbreak has been recorded. The first was discovered in 2016 by the Very Large Array Telescope in the United States. At the time, the signal’s discoverer, astronomer Shami Chatterjee, commented, “These flashes are impossible to explain without resorting to exotic physics.”

FRB 190520B is therefore the second example of a radio burst that emits repeatedly, with a weak radio emission between each burst. As if it never “turned off”.

So there are two kinds of radio outbursts? Those who only appear once and those who repeat themselves? Are they of the same character?

So far, these questions are still open. But discovering future radio eruptions can help better understand these very energetic cosmic events.

Source: natureJune 2022.

You may be interested in this article: Here are the 5 biggest mysteries in the universe. What are “fast radio eruptions”? They were first discovered in 2007, and since then no one has been able to figure out what it is. They are radio signals emitted from different directions in the cosmos and are picked up by radio telescopes. Very short, a few milliseconds, but very powerful, 100 times louder than background noise. There are almost 10,000 a year and they never cease to amaze us (…).

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