Categories: neutrinos

Almost all High-Energy Neutrinos Come From Quasars

Buried under the ice at the South Pole is a neutrino observatory called IceCube. Every now and then IceCube will detect a particularly high-energy neutrino from space. Some of them are so high energy we aren’t entirely sure what causes them. But a new article points to quasars as the culprit.

Quasars are distant supermassive black holes. During the early universe, many of these black holes were extremely active. The hot material surrounding these black holes can emit everything from x-rays to powerful bursts of radio light. In this new work, the team analyzed 7 years of data from IceCube and found an interesting correlation between quasars and high-energy neutrinos.

Map comparing quasar locations to probable neutrino sources. Credit: Plavin, et al

The data showed that most of the high-energy neutrinos originated from the centers of quasars. Their detection often occurs around the time that a quasar undergoes a strong radio burst. Since neutrinos travel at nearly the speed of light, photons and neutrinos reach Earth and nearly the same time. This suggests that the quasar radio bursts are producing neutrinos.

To explain this, the team proposed a rough model. Strong radio quasar bursts occur when hot, ionized gas near the black hole flows through strong magnetic fields. The charged particles are accelerated, causing them to emit radio light. But a rapid flow of dense plasma also causes nuclei and electrons to collide with each other. The high-energy collision of protons can create pions, which emit gamma rays and neutrinos when they decay.

How quasars might create high-energy neutrinos. Credit: Plavin, et al

This is only a rough model. To study their idea further, the team will gather more radio observations of quasars, as well as data from a neutrino telescope known as the Baikal Gigaton Volume Detector. Together this will allow them to study the central regions of quasars in detail.

Reference: Plavin, A. V., et al. “Directional Association of TeV to PeV Astrophysical Neutrinos with Radio Blazars.” The Astrophysical Journal 908.2 (2021): 157.

Brian Koberlein

Brian Koberlein is an astrophysicist and science writer with the National Radio Astronomy Observatory. He writes about astronomy and astrophysics on his blog. You can follow him on YouTube, and on Twitter @BrianKoberlein.

Recent Posts

NASA Astronaut Nicole Aunapu Mann will be the First Indigenous Woman in Space!

Nicole Aunapu Mann, the mission commander of the Crew-5 mission, will be the first Indigenous…

3 hours ago

One Exciting way to Find Planets: Detect the Signals From Their Magnetospheres

Some exoplanets could be discovered by tuning into their radio transmissions.

10 hours ago

Brand New Stars in the Orion Nebula, Seen by Hubble

The Orion Nebula is a giant cloud of gas and dust that spans more than…

11 hours ago

Satellites are Tracking Rivers of Garbage Flowing Across the Oceans

There's an ocean of human-made garbage floating through Earth's seas. From plastic straws to beverage…

21 hours ago

Lunar Rocks Have Earth's Noble Gases Trapped Inside. More Evidence That the Moon Came From the Earth

Piecing together the history of the Solar System from the traces left behind isn’t easy.…

1 day ago

Hot Stars Blast Away at gas Giants Until Only Their Rocky Cores Remain

We don't see many Neptune-sized worlds closely orbiting their star. That may be because the…

2 days ago