Some of the highest-energy protons can be found in our galaxy. A study using 12 years of data from NASA's Fermi Gamma-ray Space Telescope shows that one supernova remnant is just like that.
The particles were boosted to speeds comparable to that of light by the shock waves. Cosmic rays mostly take the form of protons, but can also contain atomic nuclei and electrons. Their paths become scrambled because they carry an electric charge. We don't know which direction they came from, so this masks their birthplace. The highest-energy light there is produced when the particles collide with the gas.
According to theorists, the highest-energy Cosmic Ray protons in the Milky Way can reach a million billion electron volts. The Pe Vatrons' sources have been difficult to pin down.
The particles are trapped by magnetic fields and cross the supernova's shock wave. The remnant can't hold them anymore, so they go off into the stars.
PeV protons have been boosted to 10 times the energy of the world's most powerful particle collider, and are on the verge of leaving our universe.
One of the suspected Pe Vatrons is at the center of our universe. There is a list of candidates. Only a few of the remnants have been found to emit high-energy rays.
A star wreck has commanded a lot of attention from the astronomy community. There is a comet-shaped cloud in the constellation Cepheus. The northern end of the supernova remnant is capped by a bright pulsar.
The remnant's extended tail was detected by the Large Area Telescope. The visible light's energy is between 2 and 3 electronvolts. Even higher-energy gamma rays were recorded from the same region. The High-Altitude Water Cherenkov Gamma-Ray Observatory in Mexico and the Tibet AS-Gamma Experiment in China have detected particles with energies of 100 trillion electron volts.
The object has been a source of interest for a while now, but we have to prove it is a PeVatron. electrons accelerated to a few hundred TeV can produce the same emission We think we have made the case that G106.3+2.7 is a PeVatron with the help of 12 years of data.
The paper detailing the findings was published in August.
A glow dominates the region to energies of a few GeV as the pulsar emits its own rays in a lighthouse-like beacon. The emission happens in the first half of the rotation. The team was able to turn off the pulsar by analyzing the last part of the cycle. There is no noticeable emission from the remnant's tail.
The additional source becomes obvious when the energy is above this. PeV protons are the particles driving this emission.
"So far, G106.3+2.7 is unique, but it may turn out to be the most bright member of a new population of supernova remnants that emit gamma rays reaching TeV energies," says Fang. More of them might be revealed through future observations by the very high-energy gamma-ray observatory.
This particular puzzle took more than a decade to be solved.
More information: Ke Fang et al, Evidence for PeV Proton Acceleration from Fermi-LAT Observations of SNR G106.3+2.7, Physical Review Letters (2022). DOI: 10.1103/PhysRevLett.129.071101 Journal information: Physical Review Letters
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