High-energy cosmic ray source has been mapped for the first time


Immediately, certain populations increased: especially three types of candidates, which are relatively common in the universe, but potentially enough to produce needles for Oh-My-God particles.

Star of Icarus

In 2008, Farrar and co-authors suggested This catastrophe, called Tidal Destruction Event (TDE), may be the source of ultra-high-energy cosmic rays.

TDE occurs when a star pulls Icarus and gets too close to a supermassive black hole. The gravitational force felt at the front of the star was so much greater than that at the back, that the star was torn into the smithy and spiraled into the abyss. The rotation lasts about a year. As it persists, two jets of matter-subatomic fragments of the destroyed star-shoot out from the black hole in opposite directions. Then, the shock wave and magnetic field in these beams may combine to accelerate the nuclear bomb to ultra-high energy, and then eject it into space.

Tidal destruction events occur approximately once every 100,000 years in each galaxy, which is cosmologically equivalent to events that occur all the time. Since galaxies track the distribution of matter, TDE can explain the success of the Ding, Globus, and Farrar continuum models.

Glennys Farrar, an astrophysicist at New York University, helped decode ultra-high-energy cosmic rays by using the Milky Way’s magnetic field.Courtesy of Glennys Farrar

In addition, the relatively short flicker of TDE solves other problems. By the time TDE’s cosmic rays reach us, TDE will have been dark for thousands of years. Other cosmic rays from the same TDE may take separate tortuous paths. Some may not arrive until centuries later. The transient nature of TDE can explain why the direction of arrival of cosmic rays seems to have only a few patterns, but there is no strong correlation with the position of known objects. “I now tend to believe that they are mostly transient,” Farrar said of the origin of the rays.

According to observations, the TDE hypothesis has recently been further developed Reported on Natural astronomy In February.

Robert SteinOne of the authors of the paper operated a telescope called the Zwicky Transient Factory in California in October 2019 when the IceCube Neutrino Observatory in Antarctica issued an alarm. IceCube found a particularly active neutrino. When even higher-energy cosmic rays scatter light or matter in the environment in which they are produced, high-energy neutrinos are produced. Fortunately, neutrinos are neutral. They travel to us in a straight line, so they point directly to the source of their parent cosmic rays.

Stein rotates the telescope in the direction of arrival of the IceCube neutrinos. He said: “We immediately saw a tidal destruction event where the neutrinos arrived.”

This correspondence makes TDE more likely to be at least one source of ultra-high energy cosmic rays. However, the energy of neutrinos may be too low to prove that TDE produces the highest energy rays. Some researchers strongly question whether these transients can accelerate the nucleus to the end of the observed energy spectrum. Theorists are still exploring how these events accelerate particles in the first place.

At the same time, other facts also divert the attention of some researchers to other places.

Starburst super wind

Cosmic ray observatories such as Auger and Telescope Arrays have also found some hot spots, namely tiny, subtle concentrations in the direction of arrival of the highest-energy cosmic rays. 2018, Auger Published The result of comparing its hot spot with the position of celestial objects within hundreds of millions of light-years. (In the event of a collision midway through the journey, the farther cosmic rays will lose too much energy.)

In the cross-correlation competition, no object performs exceptionally well-this is understandable given the experience of deflecting cosmic rays. But the strongest correlation surprised many experts: about 10% of the rays came from within 13 degrees of the direction of the so-called “exploding galaxy.” “They weren’t on my plate originally,” he said Michael Unger Member of the Karlsruhe Institute of Technology, a member of the Auger team.


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