New Light on Dark Matter and Gamma Rays in the Milky Way
The mystery of the gamma ray surplus at the heart of our galaxy, the Milky Way, is getting clearer. A brand new study suggests that this excess of gamma rays, the universe's most powerful light form, could be due to the annihilation of dark matter.
Dark matter, an unseen and elusive substance, has been long suspected as a source of these gamma rays. However, the rays' spatial spread didn't quite line up with the predicted dark matter distribution. This inconsistency led to the emergence of another theory, suggesting that ancient, rapidly spinning neutron stars, known as millisecond pulsars, might be responsible for the gamma ray production.
A New Perspective on Dark Matter Distribution
The recent study, published in Physical Review Letters, challenges previous theories about the distribution of dark matter in our galaxy. Researchers have created a model of the formation of galaxies similar to the Milky Way, taking into account the environmental conditions observed in our cosmic neighborhood. The results were strikingly similar to the real-world Milky Way.
The researchers discovered that dark matter doesn't simply radiate from the Galactic Center. Instead, it's organized in a manner comparable to stars. This implies that dark matter could indeed be responsible for the excess gamma rays observed in our galaxy.
An Unexpected Discovery
When the FERMI space telescope was aimed at the galactic center, the resulting data was surprising. The telescope detected a higher number of gamma rays than expected, causing a stir among astronomers worldwide. To explain this so-called 'gamma ray excess', numerous theories were proposed.
After much discussion, two main ideas became prominent. One theory proposed that the gamma rays were produced by millisecond pulsars. The other theory suggested they were the result of dark matter particles colliding and annihilating each other. Both theories had their shortcomings, but this new study supports the latter, indicating that the gamma ray excess is likely due to dark matter annihilation.
Understanding the Dark Matter Halo
It's well-known that the Milky Way exists within a 'dark matter halo' – a spherical region around the galaxy filled with dark matter. The extent to which this halo is not perfectly spherical, but rather elliptical or asymmetrical, was previously underestimated.
The new research findings shed light on this aspect as well, revealing that the distribution of dark matter in our galaxy is not spherical, but rather flattened and asymmetrical. This discovery not only advances our understanding of dark matter but also brings us closer to solving the mystery of the gamma ray excess in the Milky Way.