Missing Mass? It’s a Dark matter signal

Dark matter signal

Cloud of hot gas enveloping the galaxy cluster Abell 2029

Described in a recent article, scientists at the Harvard-Smithsonian Center For Astrophysics (CfA) have discovered a unidentified emission from a gas cloud enveloping a galaxy cluster which they believe might be evidence for the decay of a type of dark matter particle called a sterile neutrino. If this is confirmed it would be the first Dark Matter signal directly observed.

Dark matter is a hypothetical substance that are though to be the explanation of why there is “extra” gravity in the universe. The particles themselves don’t interact with the electromagnetic force meaning it can’t be detected by light. This makes it very hard to directly observe if you disregard the gravity it exerts. However difficult dark matter is to detect it’s calculated that it makes up about 27% of the known universe. The key difference from “normal” matter like protons and neutrons which consists of baryons, dark matter is most commonly believed to be made up of WIMPS (weakly interacting massive particle).

Dark Matter signal

Galaxies consists of a lot of stuff, is something that everyone can agree on. Because of this they exert a gravitational pull on it’s surroundings. Unsurprisingly galaxy clusters consisting of thousand of different galaxies exert a massive pull on a huge part of the part of space they are occupying. This is why scientists like to observe theses parts, the enormous pull should also house enormous quantities of Dark matter that everyone’s is trying to gather evidence of. In these giant galaxy cluster there is super hot gases in the space intersecting the galaxies. These gases consist of different elements such as Oxygen, manganese, calcium, iron and nickel. They all have a correspondent X-ray signal that telescopes here on earth can detect. The signal the scientist has detected and trying to identify does not fit in with the known elements that exists in the hot gas cloud and is believed to be the first direct evidence of dark matter, more specificly they believe its evidence of the decay of a dark matter particle called a sterile neutrino.

The researchers caution that they still don’t have enough data for this to qualify as a discovery, but with the launch of the Japanese Astro-H X-ray observatory in 2015 , which will have better resolution of this type of emission, they hope they will be able to confirm the data.

Cover image credit: Chandra/NASA/ESA, Hot gas in the central region of the perseus cluster

Content image credit: NASA/CXC/UCI/ A.Lewis et al.