For years, astronomers have sought to understand a mysterious excess of gamma rays located at the center of the Milky Way. Recent research suggests that this unusual phenomenon may stem from neutron stars, a notion previously considered by scientists. However, if this interpretation proves incorrect, the findings could represent the first substantial evidence of dark matter, according to a study published in Physical Review Letters.
Since the Fermi Gamma-ray Space Telescope first detected these excess gamma rays in 2009, various theories have emerged. Explanations have ranged from energetic stars to simple errors in instrumentation. Dark matter is believed to account for approximately 85% of the universe”s mass, yet it remains elusive and mostly interacts with matter in ways that are not easily observable. Despite extensive theoretical and experimental research, a definitive identification of dark matter has yet to be achieved.
Joseph Silk, an astrophysicist at Johns Hopkins University and a co-author of the study, emphasized the importance of dark matter, stating, “It dominates the universe and holds galaxies together.” He noted that the scientific community is constantly brainstorming new methods to detect this mysterious substance.
The research team conducted simulations that traced the evolution of the Milky Way, exploring various scenarios that could explain the gamma-ray excess. Their results indicate a strong correlation between the gamma rays and potential dark matter particle collisions, although the researchers caution that this is not conclusive evidence. They also considered the possibility that the glow originates from rapidly spinning neutron stars, known as millisecond pulsars, although this model introduced some uncertainty due to assumptions about the number of such pulsars.
The researchers acknowledge the current limitations of their findings and are committed to further investigations. They are particularly optimistic about upcoming data from the Cherenkov Telescope Array, which is expected to enhance gamma-ray observations significantly. Silk remarked, “It”s possible we will see the new data and confirm one theory over the other. Or maybe we”ll find nothing, in which case it”ll be an even greater mystery to resolve.”
