Scientists at NASA believe that they have identified the presence of the mysterious dark matter that constitutes over 85 percent of our universe. While examining the Andromeda galaxy with Fermi Gamma-ray Space Telescope, astronomers have detected the presence of Gamma rays in the centre of the galaxy similar to that found at the centre of Milky Way.
Gamma rays are the highest-energic form of light and are produced when cosmic rays and particles moving at the speed of light interact with interstellar gas clouds and starlight. The energetic waves are common in our galaxy Milky Way. However, astronomers got surprised when they saw gamma rays emission confined within the centre of Andromeda galaxy instead of spreading throughout the galaxy.
Scientists explained that several unknown sources can lead to the emission of gamma rays and dark matter is one of them. “We expect dark matter to accumulate in the innermost regions of the Milky Way and other galaxies, which is why finding such a compact signal is very exciting,” said lead scientist Pierrick Martin, an astrophysicist at the National Center for Scientific Research and the Research Institute in Astrophysics and Planetology in Toulouse, France. “M31 will be a key to understanding what this means for both Andromeda and the Milky Way.”
High concentration of pulsars at the centre of the galaxy could also potentially led to the emission of gamma rays. However, scientists are unable to resolve two objects distinctly as Andromeda galaxy is located at several light years far from Earth. Present generation telescopes are not evolved enough to identify each pulsar separately in a closely packed cluster of pulsars at such distance.
Researchers have seen gamma rays in Milky Way and Andromeda galaxy, and now they are planning to use the data to solve the mysteries of dark matter and gamma ray emissions.
“We don’t fully understand the roles cosmic rays play in galaxies, or how they travel through them,” said Xian Hou, an astrophysicist at Yunnan Observatories, Chinese Academy of Sciences in Kunming, China, also a lead scientist in this work. “M31 lets us see how cosmic rays behave under conditions different from those in our own galaxy.”
According to NASA scientists, they need more data to solve the mystery of elusive dark matter.
NASA’s Fermi Gamma-ray Space Telescope was launched on June 11, 2008, and since then it has been helping scientists in studying astrophysical and cosmological phenomena such as active galactic nuclei, pulsars, other high-energy sources and dark matter.
The study will appear in The Astrophysical Journal.