Relativistic jets extending from supermassive black holes could account for all three of the universe's highest-energy particles. Photo by PSU
Jan. 22 (UPI) -- Scientists have traced the three highest-energy particles in the universe to a single cosmic origin. The latest research -- published this week in the journal Nature Physics -- suggests neutrinos, cosmic rays and gamma rays all results from the powerful jets of supermassive black holes.
Astronomers at Penn State University found all three particle types supply the universe with similar levels off power input, despite each particle type carrying varying levels of energy.
"The fact that the measured intensities of very high-energy neutrinos, ultrahigh-energy cosmic rays and high-energy gamma rays are roughly comparable tempted us to wonder if these extremely energetic particles have some physical connections," Kohta Murase, assistant professor of astrophysics at Penn State, said in a news release.
Scientists developed a model to determine whether a single cosmic phenomenon could account for the similarities. Their analysis showed high-energy neutrinos and high-energy gamma rays can be produced by collisions between cosmic rays.
"In our model, cosmic rays accelerated by powerful jets of active galactic nuclei escape through the radio lobes that are often found at the end of the jets," said Ke Fang, a postdoctoral associate at the University of Maryland.
Previous research has shown high-energy cosmic rays emanate from "active galactic nuclei," the central regions of large galaxies that host supermassive black holes. These black holes and their large accretion disks often produce relativistic jets.
The newest model shows cosmic rays can also produce neutrinos when they collide with gas in the surrounding galaxy or galaxy cluster.
"This model paves a way to further attempts to establish a grand-unified model of how all three of these cosmic messengers are physically connected to each other by the same class of astrophysical sources and the common mechanisms of high-energy neutrino and gamma-ray production," Murase said.
Despite the promise of the new model, its creators say more observations and simulations are needed to ensure the full spectrum of each high-energy particle can be accounted for.
As new instruments designed to detect these high-energy particles come online, scientists will be better equipped to test their unifying theories.
"The golden era of multi-messenger particle astrophysics started very recently," Murase said. "Now, all information we can learn from all different types of cosmic messengers is important for revealing new knowledge about the physics of extreme-energy cosmic particles and a deeper understanding about our universe."
