Mysterious phenomenon at heart of Milky Way galaxy linked to new type of dark matter

Amazing stuff!

"“At the centre of our galaxy sit huge clouds of positively charged hydrogen, a mystery to scientists for decades because normally the gas is neutral,”  ...

“So, what is supplying enough energy to knock the negatively charged electrons out of them?”

Astronomers have called this area of ionised hydrogen gas clouds the Central Molecular Zone (CMZ). ..."

"... In this first of its kind study, scientists have taken a step closer to understanding the elusive mystery [dark] matter. They believe a reimagined candidate for dark matter could be behind unexplained chemical reactions taking place in the Milky Way. ...

The most established theory for dark matter is that it is likely a group of particles known as ‘Weakly Interacting Massive Particles’ (WIMPs), which pass through regular matter without much interaction – making them extremely hard to detect.

However, this study ... has potentially revived another type of dark matter with much, lower mass than a WIMP.

The researchers think that these tiny dark matter particles are crashing into each other and producing new charged particles in a process called ‘annihilation’. These newly produced charged particles can subsequently ionise the hydrogen gas. ...

This finding may simultaneously explain wider mysteries of our Galaxy, such as a specific type of X-ray observation found at the centre of the Milky Way – known as the ‘511-keV emission line’. This specific energy signature could also be due to the same low-mass dark matter colliding and producing charged particles."

From the abstract:

"We demonstrate that the anomalous ionization rate observed in the Central Molecular Zone can be attributed to MeV dark matter annihilations into 𝑒+⁢𝑒− pairs for galactic dark matter profiles with slopes 𝛾 >1. The low annihilation cross sections required avoid cosmological constraints and imply no detectable inverse Compton, bremsstrahlung, or synchrotron emission in radio, x- and 𝛾 rays. The possible connection with the source of the unexplained 511 keV line emission in the Galactic Center suggests that both observations could be correlated and have a common origin."

Mysterious phenomenon at heart of Milky Way galaxy linked to new type of dark matter "Unexplained chemical reactions observed at the centre of the Milky Way galaxy could be caused by the existence of a type of dark matter not accounted for in current physics."

Mysterious phenomenon at centre of galaxy could reveal new kind of dark matter (original news release) "A mysterious phenomenon at the centre of our galaxy could be the result of a different type of dark matter."

Anomalous Ionization in the Central Molecular Zone by Sub-GeV Dark Matter (open access)