This decade has been fascinating for astrophysics because of dramatic discoveries such as cosmic acceleration, exoplanets and the detection of gravitational waves from merging black holes. However, none of these breakthroughs have been as challenging and surprising as the identification of dark matter.
Most people think that the entire universe is comprised of ordinary tangible matter, or those that are made up of atoms. Scientists say that more than 80 percent of the universe is comprised of dark matter, which cannot be observed directly, but has a mass and can affect normal matter.
Various theories have been formulated about what comprises dark matter, and the common belief is that besides gravity, it shares another property with general matter.
Dark matter also comes in two forms - regular matter and anti-matter. When these two collide, they annihilate, or destroy each other. In the process, energy is conserved and a new high energy particle like a photon or gamma-ray is formed.
In a recent study, published in the journal Physics of the Dark Universe, researchers have recognized one such signature of dark matter annihilation.
The physicists studied the spatial distribution of gamma-ray emission, particularly in the Milky Way's Galactic Center. This region has higher matter density and is relatively nearby.
Should dark matter annihilation occur in this area, the location is expected to become bright. Indeed, scientists have observed a large gamma-ray signature that extends beyond hundreds of light years.
There are other possible sources of gamma-ray, such as, a large number of rapidly spinning pulsars emitting electromagnetic radiation. Hence, the scientists revisited some earlier observations and applied new data reduction methods in order to better assimilate the location of gamma-ray emissions.
The findings demonstrated that the distribution of the radiation works better with models of dark matter annihilation than with pulsar models. If confirmed, the study can be used as evidence about the mysterious dark matter.