(Blazar NGC 4872 / Wikimedia Commons)
Physicists working at the Baikal Neutrino Telescope have reported the detection of a high-energy neutrino candidate from the blazar PKS 0735+17, which is now in a state of increased activity.
It is noteworthy that the discovery was made several hours after the neutrino from the same blazar was detected by the IceCube detector in Antarctica.
One of the important directions in cosmic ray research is the registration of astrophysical neutrinos of high and ultrahigh energies.
These particles are born as a result of the decay of mesons or the interactions of cosmic rays with atomic nuclei and photons.
Due to the fact that neutrinos are very light, have no charge and interact extremely weakly with matter, their energy spectrum and direction of arrival can be used to determine what processes are taking place in different astrophysical objects, such as supernovae, black holes and active galaxies.
One of the types of sources of cosmic neutrinos are blazars, active nuclei of distant galaxies containing a supermassive black hole that absorbs matter from the accretion disk
Blazars’s accretion disk is responsible for the generation of relativistic jets directed at a small angle to the terrestrial observer.
It is with the blazar and its jets that the first reliable case of detecting ultrahigh-energy neutrinos and a number of other possible sources of neutrinos is associated.
On December 8, the IceCube neutrino detector in Antarctica recorded the IceCube-211208A event - a muon "track" formed during the interaction of an astrophysical neutrino with an energy of about 172 teraelectronvolts with ice.
The direction of arrival of the particle indicated one of the brightest blazars in the radio range, PKS 0735+17.
At present, the blazar is in a state of flare, demonstrating an increased radiation flux in the optical, X-ray, gamma and radio wave ranges.
Now, scientists from the Baikal-GVD collaboration, working at the Baikal Neutrino Telescope, reported that, 3.95 hours after the registration of neutrinos, IceCube recorded the arrival of neutrinos with an energy of 43 teraelectronvolts.
The arrival area of the particle is 4.68 angular degrees from PKS 0735+17 and 5.3 degrees from the best candidate area determined from IceCube data.
The statistical significance of the event was estimated at 2.85 sigma.
Thus, we can talk about the first case of registering a candidate for high-energy neutrinos from one astrophysical source with two neutrino telescopes at once.
At present, scientists continue to analyze the data obtained by the Baikal telescope and observe the blazar using ground-based telescopes.
Source:
- The Astronomer’s Telegram: https://www.astronomerstelegram.org/?read=15112