January 15, 2020
A high-altitude observatory has detected 9 astrophysical sources emitting gamma rays with extraordinarily excessive energies.
A. U. Abeysekara et al. (HAWC Collaboration), Phys. Rev. Lett. (2020)
In 2019, astrophysicists observing the Crab Nebula detected the highest-energy photons ever seen—with energies above 100 TeV. Now, a collaboration working the Excessive Altitude Water Cerenkov (HAWC) Observatory in Puebla, Mexico, has surveyed the sky to map out different related high-energy-gamma-ray sources, revealing a complete of 9. Such maps may assist researchers perceive the astrophysical origin of essentially the most energetic particles and photons raining down on Earth from the cosmos.
Gamma rays are often generated from accelerated charged particles, akin to electrons or protons. However to provide 100-TeV photons, the particles’ power needs to be boosted by extraordinarily highly effective cosmic accelerators, with the main candidates being supermassive black holes, supernova remnants, pulsars, and energetic galactic nuclei. There may be nonetheless uncertainty, nevertheless, concerning the actual acceleration mechanisms. To elucidate them, researchers are aiming to detect extra of the uncommon photons and hint them again to their sources.
HAWC detects gamma rays by observing showers of secondary particles produced when the rays hit the ambiance. By measuring the secondary particles at quite a few places on the bottom, the power and arrival route of the gamma rays could be inferred. The collaboration produced two maps of the sky—accumulating solely photons above 56 TeV and 100 TeV, respectively. The maps revealed 9 sources above 56 TeV, three of which additionally emit above 100 TeV. The researchers say that each one the sources are doubtless in our Galaxy, they usually lie near highly effective pulsars, which means that the pulsar setting could also be key to producing ultrahigh-energy emission.
This analysis is printed in Bodily Evaluation Letters.
Matteo Rini is the Deputy Editor of Physics.