Researchers from the Shibaura Institute of Technology in Tokyo have proposed that active galactic nuclei, including blazars, could be the source of elusive neutrinos that continually pass through Earth. The findings appear in a reputable astrophysics journal.
Neutrinos are often described as ghost particles because they carry no electric charge and have almost no mass. They can slip through dense dust, stellar material, and other barriers that stop most particles, making them incredibly hard to detect. Each second, trillions of neutrinos traverse the human body without leaving a trace.
Active galactic nuclei emit a broad spectrum of electromagnetic radiation, ranging from faint radio waves to extremely energetic hard gamma rays. Scientists also note that blazars release cosmic rays, and these rays can interact with light particles to produce neutrinos.
To explore the mystery of neutrinos further, the researchers monitored bursts from a sample of blazars, enabling them to estimate the weekly gamma-ray flux. They then calculated the corresponding neutrino flux for each gamma-ray burst and established a relationship that scales with the blazar’s gamma-ray activity during calmer periods.
By comparing neutrino estimates over weekly intervals and longer, multi-year timescales with data from a leading neutrino observatory, scientists were able to place upper limits on how much blazar flares contribute to the overall neutrino flux.
Astrophysicists hope these calculations will illuminate the role blazars may play in producing neutrinos and shaping their cosmic origins.
In parallel, researchers have carried out what is described as one of the most expansive cosmological computer simulations to date, pushing the boundaries of how such simulations model the universe.