The Andromeda Galaxy, also known as M31 is the closest galaxy of earth. It is the nearest major galaxy to the Milky Way and was often referred to as the Great Andromeda Nebula in the older text.
Now, NASA's Fermi mission said that a strange gamma-ray signal at the center of the neighboring Andromeda galaxy that could indicate the presence of the mysterious stuff known as dark matter. This dark matter or the collective glow of many spinning neutron stars, called pulsars.
Gamma rays are the highest-energy form of light, produced by the universe's most energetic phenomena. Now Fermi has found that the Gamma Rays in Andromeda Galaxy are confined to the galaxy's center instead of spread throughout. Scientist presumed that the emission may come from several undetermined sources or unknown substance from the entire universe.
Lead scientist and an astrophysicist Pierrick Martin said that 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. Another possible source for this emission could be a rich concentration of pulsars in M31's center.
This spinning neutron star weighs as much as twice the mass of the sun and among the densest objects in the universe. A small amount of neutron star matter would weigh a billion tons on Earth and some pulsars emit most of their energy in gamma rays. To identify whether the Gamma Rays are coming from these objects, scientists can apply what they know about pulsars from observations in the Milky Way to new X-ray and radio observations of Andromeda.
Now using NASA's Fermi Gamma-ray Space Telescope, scientists has detected a similar gamma-ray signature in both M31 and the Milky Way. They can use this information to solve mysteries within both galaxies. M31 emits few Gamma Rays and indicating fewer cosmic rays coming from there. Cosmic rays are usually thought to be related to star formation. The absence of gamma rays in the outer parts of M31 suggests either that the galaxy produces cosmic rays differently, or that they can escape the galaxy more rapidly.
A research scientist at NASA, Regina Caputo said that Milky Way galaxy is so similar to Andromeda Galaxy it really helps to study a lot of things.While more observations are necessary to determine the source of the gamma-ray excess. The discovery provides an exciting starting point to learn more about both galaxies, and perhaps about the still elusive nature of dark matter.
