Researchers find new clues to origin of most energetic cosmic particles
Cosmic-ray electrons are considered the “most energetic electrons and positrons.”
In galaxies, extreme objects like supernova remnants, pulsars, and black holes unleash powerful energy, accelerating particles to speeds near the speed of light.
These objects emit incredibly high-energy charged particles and gamma rays.
Among these high-energy particles are cosmic-ray electrons (CRe), elusive messengers from the cosmos.
Cosmic-ray electrons are considered the “most energetic electrons and positrons.”
Interestingly, these possess energies over one teraelectronvolt (TeV), which is 1000 billion times higher than the energy of visible light.
But their origins remain shrouded in mystery. Scientists turn to powerful instruments like the H.E.S.S. Observatory based in Namibia to unravel this cosmic puzzle.
Interestingly, H.E.S.S. has now uncovered fresh clues about the origins of these particles.
The data suggests that these high-energy electrons likely originate from sources relatively close to our solar system.
“We can conclude that the measured CRe most likely originates from very few sources in the vicinity of our own solar system, up to a maximum of a few 1000 light years away, a very small distance compared to the size of our Galaxy,” said Kathrin Egberts, corresponding author from the University of Potsdam.
Analysis of HESS data
Ground-based detectors indirectly observe cosmic ray electrons by detecting the particle showers they produce in the atmosphere.
By studying these showers, scientists can glean valuable insights into the properties of the original cosmic ray.
However, distinguishing showers from electrons or positrons from the more common showers from protons and nuclei is a significant challenge.
The H.E.S.S. Observatory uses multiple 12-meter telescopes to detect Cherenkov radiation from air showers, primarily to study gamma-ray sources. However, its data can also identify cosmic-ray electrons within these showers.
For the uninitiated, Cherenkov radiation is produced when a charged particle, like an electron, travels at a faster speed through a dielectric medium, such as water.
In the new study, the researchers analyzed data from the HESS telescopes for a decade. Furthermore, they incorporated advanced algorithms to identify cosmic-ray electrons amidst background noise efficiently.
“We were able to put severe constrains on the origin of these cosmic electrons with our detailed analysis for the first time”, said Werner Hofmann, co-author from the Max-Planck-Institut für Kernphysik.
Origin likely from nearby sources
Through this approach, H.E.S.S. researchers gathered unprecedented information about cosmic-ray electrons.
For the first time, they could gather data on cosmic-ray electrons at the highest energy range, extending up to 40 TeV.
By collecting data on cosmic-ray electrons up to 40 TeV, the researchers could observe a sudden drop-off in their energy distribution.
This led them to conclude that the measured CRe likely originated from a few nearby sources, perhaps somewhere close to the home galaxy.
“The very low fluxes at larger TeV limit the possibilities of space-based missions to compete with this measurement. Thereby, our measurement does not only provide data in a crucial and previously unexplored energy range, impacting our understanding of the local neighbourhood, but it is also likely to remain a benchmark for the coming years”, concluded Mathieu de Naurois, CNRS researcher from the Laboratoire Leprince-Ringuet, in the press release.
Source: https://interestingengineering.com