The almost massive, subtomic particles called neutrinos that affect the formation of galaxies have long been a cosmological mystery that physicists have tried to measure since the discovery of particles in 1956.
But an international research team, including Nauki Yoshida, principal investigator at the Kavali Institute for Physics and Mathematics in the Universe (Kavali IPMU), who is also a professor in the physics department at the University of Tokyo, has created a global simulation. The role of neutrinos in the evolution of the universe. His study was recently published Astrophysical Journal.
University of Missouri Science and Technology .G (Missouri S&T) Cosmologist Dr. Shan Saito, an assistant professor of physics and a team researcher, said the work was a milestone in the process of creating the universe. Saito Kavali is also a visiting associate scientist at IPMU.
The team used a system of differential equations called Vitlavo-Poison equations to explain how neutrinos in the universe move with different values assigned to their set.
Figure 1: Density distribution of neutrinos (left) and dark matter (right) in a cosmic mass structure. While neutrinos move rapidly and seem to disperse, dark matter distribution composes global magic such as filamentary structures. Credit: Kavali IPMU
This technique accurately represents the velocity distribution function of neutrinos and follows its development over time. Researchers then investigated the effects of neutrinos on galaxy formation and evolution.
Their results show that neutrinos will repress a group of dark objects in the ress universe – and in turn, suppress galaxies. They found that neutrino-rich regions are strongly related to large amounts of galaxy clusters, and that the effective temperature of neutrinos varies significantly depending on the mass of neutrinos.
Researchers say that the most rigorous experiments to estimate the neutrino mass are global observations, but this can only be relied upon if the simulation predictions are accurate.
Figure 2: Researchers’ Vlasov-Poison simulation (left) predicts a simpler and less noisy distribution of neutrinos than a traditional N-body particle simulation of neutrion gravitational interaction (right). Credit: K IPMU
“Overall, our findings are consistent with both theoretical predictions and the results of previous simulations,” says Dr. Kuter Kohji Yoshikawa of Tsukuba University’s Center for Computational Science and lead author of the study. “It ensures that the results of the full simulation approaches agree with each other.”
“Our simulations are important because they determine the barrier at an unknown amount of neutrino mass,” says the Missouri S&T site. “Neutrinos are the lighter particles we know. We have only recently learned that neutrinos derive mass from discoveries made at the 2015 Nobel Prize in Physics. ”
The award was given to two scientists, including Takaki Kajita, the principal investigator at Kavali IPMU, who is also the director of the Cosmic Ray Research Institute at the University of Tokyo, for their unique discovery that one type of neutrino could transform into another.
“Our work could eventually lead to a stronger decision of the neutrino group,” says Saito.
Postdoctoral Fellow of the Yukawa Institute for Theoretical Physics at Kyoto University, Dr. Satoshi Tanaka was the fourth member of the study entitled “Cosmological Vlasov – Poison Simulation Stf Structure Formation with Relic Neutrinos: Nonlinear Clustering and Neutrino Mass”.
Reference: “Cosmological Vlasov Rel Poison Simulations of Structure Formation with Relic Neutrinos: Nonlinear Clustering and the Neutrino Mass” by Kohji Yoshikawa, Satoshi Tanaka, Naoki Yoshida and Shun Saito, 30 November 2020, Astrophysical Journal.
DOI: 10.3847 / 1538-4357 / ABBD46
