• Physics 15, s106
An evaluation of 12 years of gamma-ray observations has allowed researchers to pinpoint a Galactic supply of high-energy cosmic rays.
Cosmic rays continually bombard Earth from all instructions. The vitality spectrum of those particles—that are principally protons and different atomic nuclei—roughly follows an influence regulation. Many of the particles having energies of some GeV or much less, however a spectral function at round 1 PeV hints at a fraction of particles accelerated to a lot increased energies. These high-energy cosmic rays are thought to originate from inside our Galaxy, however the id of the accelerators, or “PeVatrons,” that produce them stays a thriller (see Viewpoint: Indicators of PeVatrons in Gamma-Ray Haze). Now, after analyzing 12 years of knowledge taken by the Fermi Giant Space Telescope (Fermi-LAT), researchers level to a supernova remnant (SNR) as a possible supply [1].
The exact origin of cosmic rays is tough to pin down as a result of the trajectories of those charged particles are perturbed by interstellar magnetic fields. Astronomers map cosmic-ray sources not directly by observing the gamma radiation created when cosmic rays work together with interstellar materials close to to the place astronomers suppose the particles had been created. However the very-high-energy radiation which may signpost a PeVatron may also be generated by different processes, comparable to inverse Compton scattering of cosmic background radiation by relativistic electrons.
Ke Fang, on the College of Wisconsin-Madison, and colleagues studied G106.3 + 2.7, an SNR about 2600 mild years away, in search of a mechanism that might match each the gamma radiation detected from it by Fermi-LAT and the x rays and radio waves measured by different observatories. They discovered that the info strongly help the SNR being a PeVatron, whereas being incompatible with an inverse-Compton-scattering origin for the radiation. Fang says that she hopes that G106.3 + 2.7 would be the first of many galactic PeVatrons to be found.
–Marric Stephens
Marric Stephens is a Corresponding Editor for Physics Journal primarily based in Bristol, UK.
References
- Ok. Fang et al., “Proof for PeV proton acceleration from Fermi-LAT observations of SNR G106.3 + 2.7,” Phys. Rev. Lett. 129, 071101 (2022).
