The cosmic radio wave AT2019dsg, discovered in 2019, is said to be high-energy neutrinos known as “ghost particles” that create black holes that tear stars apart.Research guidelines published in the Astrophysical Journal earlier this monthAfter analysis, it was found that AT2019dsg was very normal, at least until the black hole tore through the stars, and the energy it emitted was not enough to produce “ghost particles”.

AT2019dsg was first discovered on April 9, 2019, from a galaxy 750 million light-years away. X-ray and radio observations confirmed that it came from a supermassive black hole 30 million times the mass of the Sun, once emitting a flash of flames and forming a tidal interference event (TDE).

In order to tear a star apart, the star must first be captured by the gravitational pull of the black hole; The large tidal force of the black hole first extends and then tears the star apart. TDE refers to the process by which a black hole tears through a star. Half the fragments of a scattered star orbit around a black hole, emitting light and generating great heat and light before being ejected from the event horizon; The other half of the star fragments was thrown into space.

A star splitting is closer to the star’s black hole

About 6 months after the appearance of AT2019dsg, on October 1, 2019, an ice cube neutrino detector at the South Pole, IC191001A, discovered a neutrino with an energy level of more than 200 terelectron volts.

Neutrinos (neutrinos) are called “ghost particles” because they have almost zero mass, can fly at speeds close to the speed of light, and do not actually interact with ordinary objects; However, sometimes neutrinos interact, and this works IceCube’s principle: When neutrinos encounter Antarctic ice sheets, they produce lightning.

Depending on the characteristics of the light propagation method and the brightness, scientists can estimate the energy level of neutrinos and the direction of their source. Previously, IC191001A was alleged to be in the direction of AT2019dsg, so only 0.2% of scholars estimated that neutrinos had nothing to do with this TDE.

However, the argument raises some important issues.Yvette Sandes, an astronomer at the Harvard Center for Astrophysics, who led the research, If this neutrino somehow comes from AT2019dsg, why does the academic world not find a neutrino associated with a supernova at this distance or near? Because the latter is more common, it has the same energy speed.

Neutrino energy can be calculated from light propagation and brightness

The research team led by Sandis used Chile’s Atacama Large Millimeter / Submillimeter Array (ALMA) to monitor AT2019dsg at radio wavelengths of more than 500 days, and found that TDE glows at radio wavelengths for approximately 200 days. To darken slowly.

The team also calculated the total amount of energy flowing out of the TDE, which is similar to the amount of energy emitted by the Sun in 30 million years, including TDE’s range energy emissions, Ib and Ic supernova type.

However, to produce neutrinos with the same energy as IC191001A, the outflow energy must be about 1,000 times larger. Also, the energy flow must have a strange geometric shape, which is not the case with AT2019dsg. In other words, AT2019dsg is so common that a new statement may be needed to explain the emergence of IC191001A.

However, humans still have a lot of ignorance about neutrinos and TDE, which means that AT2019dsg will continue to gain attention. Sendus added that Team AT2019dsg could be re-examined as the black hole is still eating away at the stars.

Source:
Science Alert, A mysterious ‘ghost particle’ probably did not come from the food of a black hole, 16 October 2021

Report:
Sendus, Y., Alexander, K.D., Berger, e. (2021). Radial observations of a typical flow outflow from the tidal disturbance event AT2019dsg. Astrophysical Journal Volume 919 No. 2. doi: 10.3847 / 1538-4357 / ac110a

Text / Alan Chiu