Three of the strangest sorts of particles that we can detect on Earth may all come from the same place. Ultra-high energy cosmic rays, high-energy neutrinos, and powerful gamma rays could all be born in the chaos of a black-hole jet.
Ultra-high energy cosmic rays come from space and have energies millions of times higher than anything we can produce in an accelerator on Earth. They were first discovered in 1962, and since then no one has been able to figure out for sure where they originate.
The same is true for neutrinos and gamma rays with extremely high energies. Now, at the University of Maryland and at Pennsylvania State University have simulated a way to get all three types of particles from a single source.
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The researchers suspected that these particles might share a common origin because they all bring around the same amount of energy to detectors on Earth.
鈥淓ach particle has a different energy, but somehow the total energy supply from each type is very comparable,鈥� says Murase. 鈥淭his is very weird, and it implies that they might have a physical connection.鈥�
Speedy offspring
Murase and Fang created a simulation of聽a cosmic ray鈥檚 path from the centre of a cluster of galaxies to detectors on the ground. First, the protons that make up the cosmic ray are accelerated by powerful jets of plasma that shoot away from supermassive black holes.
The resulting ultra-high energy cosmic rays bounce around within the cluster of galaxies, smashing into clouds of gas and other matter. These interactions create particles called pions which they decay into neutrinos and gamma radiation. The cosmic rays, along with their offspring, eventually leak into intergalactic space, where some of them make their way towards Earth.
The simulation matched the amount of the three types of high-energy particles we have already detected, as well as their measured energies. at NASA鈥檚 Goddard Space Flight Center in Greenbelt, Maryland says this solution to the mystery source of high-energy particles in our cosmos sounds plausible.
鈥淚f you get the high-energy cosmic rays produced in the jets, you鈥檙e also going to get the others,鈥� she says. 鈥淚t鈥檚 an elegant solution.鈥�
Nature Physics
Read more: Black holes that shred stars burp out cosmic rays and neutrinos
