For many years, astronomers have been intrigued by an enigmatic gamma ray glow that appears to originate from the center of the Milky Way galaxy. Recent theories propose two main explanations: the glow could be a result of dark matter particles colliding, or it may stem from rapidly rotating neutron stars known as pulsars.
A study published in the journal Physical Review Letters does not provide a definitive answer but emphasizes that both theories hold equal weight. If the first theory is validated, it could represent the first tangible evidence of dark matter, which is believed to constitute over 26 percent of the universe.
Co-author and astronomy professor at Johns Hopkins University, Joseph Silk, remarked, “Dark matter dominates the universe and holds galaxies together. It”s extremely consequential, and we”re constantly brainstorming ways to detect it.” He added, “Gamma rays, particularly the excess light we observe at the center of our galaxy, could be our first clue.”
To explore the formation of the Milky Way, Silk and his international team developed a dark matter map to pinpoint its likely locations. They hypothesize that billions of years ago, smaller dark matter structures merged at the galaxy”s center, increasing the frequency of collisions among these clumps.
Through simulations of these interactions, the researchers discovered that their dark matter map aligned with existing gamma ray data acquired from NASA”s Fermi Gamma-ray Space Telescope. Although this correlation is compelling, scientists remain cautious about asserting that the glow is definitively linked to dark matter, as pulsars may also be responsible.
Fortunately, the forthcoming Cherenkov Telescope Array Observatory, an international initiative featuring 60 telescopes situated in La Palma, Spain, and the Atacama Desert in Chile, aims to clarify this mystery. With enhanced imaging capabilities, researchers hope to pinpoint the source of the long-standing gamma ray anomaly at the Milky Way”s heart.
“A clean signal would be a smoking gun, in my opinion,” Silk stated.
In the meantime, Silk and his colleagues are also investigating neighboring dwarf galaxies to assess the distribution of dark matter and its correlation with existing gamma ray maps. “It”s possible we will see the new data and confirm one theory over the other,” he concluded. “Or perhaps we”ll find nothing, which would present an even greater mystery to solve.”
