A team of astrophysicists has breathed new life into the controversy over the mysterious gamma-ray glow at the center of the Milky Way. New simulations suggest that dark matter may be able to explain gamma-ray anomalies at the center of the Milky Way, and the findings also suggest that early galaxy merger events may have caused dark matter distributions to somehow match observations from the Fermi telescope.
A long-standing cosmic mystery about why the center of the Milky Way produces strange, high-energy gamma rays has once again come into focus. A research team led by Dr. Moorits Muru, Dr. Noam Libeskind and Dr. Stefan Gottlöber from the Leibniz Institute for Astrophysics (AIP), together with Professor Yehuda Hoffman from the Racah Institute of Physics at the Hebrew University of Jerusalem and Professor Joseph Silk from the University of Oxford, tried to unravel this mystery.
The team's research results have been published in Physical Review Letters. The research relies on cutting-edge cosmological simulations to reexamine this age-old question. The results show that dark matter, which is considered to constitute the main component of the universe, is expected to become the main explanation for the mysterious radiation first discovered by NASA's Fermi gamma-ray space telescope.
Scientists have been studying this intense, high-energy light—known as the Galactic Center Excess—for years, referring to unusually intense gamma rays in the core of the Milky Way. A previously popular view was that dark matter particles could collide, annihilate and release high-energy gamma rays.
But as data continues to accumulate, the pattern of radiation distribution does not exactly match the expected distribution of dark matter in the Milky Way. From this, scientists have proposed another possibility: the luminous phenomenon may originate from a group of extremely old, rapidly rotating neutron stars, namely millisecond pulsars.
This time the research team changed their previous thinking and used a high-resolution simulation tool called "Hestia" to simulate the formation process of galaxies in an environment similar to that of our universe, and reconstruct the turbulent history of the Milky Way, including early mergers. The study found that these events may have reshaped the distribution pattern of dark matter in the center of the Milky Way.
The results reveal a more complex, non-spherical structure of dark matter than previous models, replicating the actual observed gamma-ray distribution without introducing large numbers of pulsars.
"The history of the Milky Way during collisions and growth will leave a unique fingerprint on the distribution of central dark matter," the research team said. "When these factors are included, the gamma-ray signal looks more like it is produced by dark matter."
The study doesn't end the debate, but it does reinvigorate dark matter as one of the prime suspects in astrophysics' most fascinating mysteries. In the future, equipment such as the Cherenkov Telescope Array will further observe higher-energy gamma rays, which may be able to test the above theory more effectively.
"This study provides a new perspective for interpreting mysterious signals in the sky," the team added. "In the future, we will either confirm that dark matter can leave observable traces, or gain a new understanding of the Milky Way itself."
Compiled from /ScitechDaily