A new mysterious signal is repeated from a distant galaxy, and it’s strange

(ORDO NEWS) — A newly discovered source of repetitive fast radio bursts has deepened the mystery of what exactly could be causing these powerful bursts.

The source, first discovered in 2019 and named FRB 190520B, appears to frequently emit millisecond bursts of powerful radio waves.

This allowed astronomers to conduct analyzes that reveal information about where they come from in the universe and the space around it. These analyzes show that there is probably more than one mechanism in the vast cosmos that is capable of producing these strange flares.

Fast radio bursts (FRBs), as the name suggests, are very fast bursts of radiation (only milliseconds long) that flash brightly in the radio spectrum.

Most of them come from other galaxies (only one source has been found in the Milky Way) and they are very bright, throwing out as much energy in an instant as 500 million suns.

Most of these flares have only been detected once: they appear out of nowhere, flash once, after which we never see them again. This makes them largely impossible to predict and very difficult to track and study.

But several sources (three, to be exact) have been found to be repetitive, and they offer a tempting opportunity to understand what’s going on. Maybe.

The bursts found in the Milky Way originated from dead stars called magnetars, suggesting that at least some of them are caused by magnetar eruptions. But there are still many unknowns.

“Are those that repeat themselves different from those that don’t?” says astrophysicist Kshitiy Aggarwal of West Virginia University.

The discovery signal from FRB 190520B arrived on Earth in May 2019, detected by the Five Hundred Meter Aperture Spherical Radio Telescope (FAST) in China, and detected in data in November of that year.

Subsequent observations of the position in the sky showed that the source repeats itself.

Additional observations were made using the National Science Foundation’s Carl G. Jansky A very large array revealing an exciting set of features. The signals were coming from the outskirts of a very old dwarf galaxy, almost 4 billion light-years away.

In the intervals between radio bursts, the source emits weaker radio emission. This suggests that fast radio bursts come from a compact constant radio source, the nature of which is unknown.

If you’re a fan of fast radio bursts, this might sound familiar to you. This is because these characteristics are similar to another known repetitive fast radio burst, FRB 121102.

It was the first FRB ever traced to its source, the outskirts of a very old dwarf galaxy 3 billion light-years away. And this is also associated with a compact constant radio source.

“Now we have two of these, and that raises some important questions,” says astronomer Casey Lowe of the California Institute of Technology.

We don’t know, for example, if one-time FRBs repeat at energies too low for us to detect. But scientists have thought for some time that there could be at least two different mechanisms for the bursts, and the discovery of FRB 190520B is consistent with that idea.

This may mean that different bursts are emitted by different objects or emitted by the same object at different stages of its evolution.

Magnetars are a type of neutron star – the collapsed, superdense core of a massive star after it has gone supernova. and died, but they also possess an extremely powerful magnetic field. It is possible that normal neutron stars and magnetars emit FRB differently.

Further analysis shows that another feature of fast radio bursts may not be as useful for measuring the universe as astronomers might have thought.

This characteristic is called a measure of dispersion and is related to how light is scattered by rarefied gas in the space between us and the source. Higher frequency waves propagate more efficiently than lower frequency waves and this can be used as a reference for measuring distance.

For FRB 190520B, the dispersion measure suggests that the source is between 8 and 9.5 billion light waves. years. However, independent distance measurements show that the galaxy is not that far away.

“This means that there is a lot of material near the FRB that could confuse any attempt to use it to measure gas between galaxies,” says Aggarwal. “If that’s the case with others, then we can’t count on FRBs being used as cosmic yardsticks.”

On the other hand, this assumes that the constant radio source emitting the FRB is in a very complex plasma. environment, which corresponds to the characteristics of a recent superluminous supernova. This suggests that whatever the source, it was formed quite recently – a “newborn” source of FRB.

“We also postulate that FRB 121102 and FRB 190520B represent the initial stage in the evolution of the FRB population,” says the astronomer. Di Li of the National Astronomical Observatory of the Chinese Academy of Sciences in China, who led the study.

“A consistent picture of the origin and evolution of FRBs is likely to emerge in just a few years.”

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