Early Galaxies May Be Sending Neutrinos to Earth, New Study Reveals

James Webb Space Telescope Identifies High-Redshift Little Red Dots

Shortly after the James Webb Space Telescope became operational, its infrared optics targeted the early Universe and revealed an abundance of small red objects. These supermassive black holes are believed to be embedded in gaseous envelopes formed directly after massive clouds of gas collapsed.

Producers of High-Energy Neutrinos and Hidden Gamma Rays

Neutrinos are electrically neutral elementary particles with masses near zero. While high-energy neutrinos originating from across the universe have been detected on Earth, the origin of the all-sky energy background remains a mystery. Sources that produce high-energy neutrinos generally also produce gamma rays. This discrepancy indicates that the source of neutrino background radiation must consist of hidden objects from which gamma rays cannot easily escape.

Numerical Calculations and Research Methodology

The research was led by Riku Kuze, a Ph.D. student at the Center for Gravitational Physics and Quantum Information at the Yukawa Institute for Theoretical Physics (YITP). Kuze was joined by collaborators from the Center for Multimessenger Astrophysics at Penn State, the Frontier Research Institute for Interdisciplinary Sciences at Tohoku University, and the Kavli Institute for Astronomy and Astrophysics at Peking University. They then performed numerical calculations evaluating the neutrino spectrum based on particle acceleration, secondary particle production, and cooling processes.

“In the scenario we considered, abundant photons and dense gas are expected to exist around the central black hole in a Little Red Dot, which may allow such collisions to occur efficiently,” Riku Kuze explained in a press statement published by Kyoto University. The results indicate that if particle acceleration occurs in these buried black-hole environments, Little Red Dots can produce high-energy neutrinos while suppressing gamma rays.

Frequently Asked Questions

What are Little Red Dots?

Little Red Dots are small red galaxies discovered by the James Webb Space Telescope in the early Universe, existing between 0.6 and 1.6 billion years after the Big Bang, containing growing supermassive black holes.

How do Little Red Dots produce high-energy neutrinos?

According to research led by Riku Kuze, protons and other high-energy particles collide with surrounding photons and dense gas within the gaseous envelopes surrounding the central black holes, generating neutrinos that escape while gamma rays are absorbed or scattered.

Why are gamma rays missing from these sources?

Thick gas envelopes surrounding the supermassive black holes trap or suppress gamma-ray emissions, preventing them from contributing to the observed gamma-ray background on Earth while allowing neutrinos to escape.