New research: Mysterious radio bursts come from the instant a neutron star collapses into a black hole | fast radio bursts | gravitational waves

There are many magical stars in the infinite and vast universe that people can hardly imagine. The picture shows a schematic diagram of the merger of two neutron stars. (Shutterstock)

[The Epoch Times, April 04, 2023](Compiled and reported by Epoch Times reporter Zhang Bingkai) There are fast radio bursts (FRB, Fast Radio Burst) of unknown origin in the universe. The latest research in astronomy believes that these mysterious fast radio bursts are likely to come from a special kind of neutron star, Blitzar.

According to a report by the technology news website Ars Technica on March 28, the latest research believes that it is likely that a huge Blitzar emitted a radio burst when it suddenly collapsed. The collapsed Blitzar was originally formed by the merger of two small neutron stars, but its own strong magnetic field will slow down the rotation speed following the merger, causing the star to collapse following a few hours and turn into a black hole. Therefore, Blitzar’s existence time is only a few hours, or it can be translated as “flash star”.

Because this kind of collapse occurs only once, the release of fast radio burst energy during the collapse also occurs only once, which is why astronomers have not found a second identical radio burst from the same source.

What is the mass of a neutron star before it collapses? There is no definite answer yet. Scientists also don’t know whether neutron stars will survive as neutrons or will be compressed into the form of more microscopic particles called quarks. But scientists believe that the neutron star’s rotation speed plays a key role, it can resist its own huge gravitational force without collapsing, and its own magnetic field will interact with charged particles in the environment, thereby slowing down the star’s rotation speed, eventually causing The neutron star collapses into a black hole, releasing a lot of energy in the process.

Scientists have previously discovered that fast radio bursts originate from cosmic space with strong magnetic fields. At the same time, some radio bursts will appear repeatedly; while others are just a one-time burst, which probably indicates that there is a Blitzar in that cosmic space, and the neutron star that is the source of the radio burst is also destroyed during its generation process.

Schematic illustration of the detection of fast radio bursts (FRBs) from distant stars by instruments on the Earth’s surface. (Shutterstock)

The latest research utilizes two types of observations, one is the Laser Interferometer Gravitational-Wave Observatory/Virgo Interferometer (LIGO/VIRGO) gravitational wave detection project, which can identify gravitational waves produced when neutron stars merge; the other is the Canadian Hydrogen Intensity Mapping Experiment (Canadian Hydrogen Intensity Mapping Experiment), which is an observatory designed for other purposes, but can be used to pinpoint the source of radio bursts.

The research method is very simple, that is, to check the gravitational wave events and radio burst events simultaneously observed by two experimental devices at approximately the same time point, if they come from the same space region and the detection time is within one day, it can be considered that the two The observations come from the same cosmic event. The latest study analyzed the gravitational waves emitted by 21 neutron star mergers, and one of them, named GW 190425, matched the fast radio burst FRB 20190425A that appeared 2.5 hours later. Since the detection of the source of gravitational waves is not very accurate, the researchers judge that the possibility of radio bursts occurring in the same cosmic region is 70%. However, because the two events are at the same distance from Earth, and observations of neutron star mergers are relatively rare, the researchers believe there is only a 0.004 chance that the two events are not related.

According to the report, if it is confirmed that the fast radio burst FRB 20190425A originated from a Blitzar, then this can verify that the previous theory that “neutron stars collapse suddenly following merging” is correct. According to the gravitational wave detection data, scientists have further given that the masses of the two neutron stars before the merger were 1.35 and 2.0 solar masses respectively, and the mass of the neutron star following the merger is 3.2. According to theoretical calculations, a neutron star with a mass of more than 3.0 will collapse to form a black hole because of its mass.

The latest study was published March 27 in theNature‧Astronomy“Science Journal. ◇

Responsible editor: Sun Yun#


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