One thing is stopping the fastest-moving particles in area from coming into the middle of our galaxy.
The middle of the Milky Approach could also be extra uncommon than astronomers thought, based on a brand new examine.
For this examine, a group of researchers from the Chinese language Academy of Sciences in Nanjing investigated a map of radioactive gamma rays – the biggest power type of gentle within the universe – exploding in or across the heart of our galaxy.
The map revealed that one thing close to the middle of the galaxy accelerates particles to unimaginable speeds – nearly to the velocity of sunshine – and creates an abundance of cosmic rays and gamma rays not removed from the galactic heart. Nevertheless, though the galactic heart is emitting a storm of high-energy radiation into area, one thing near the core of the Milky Approach prevents a lot of the cosmic rays from different elements of the universe from coming into our galaxy, the group mentioned within the journal Nature Communication.
The researchers described the impact as an invisible “protect” across the galactic heart and that retains the density of cosmic rays considerably decrease than the baseline degree seen in the remainder of our galaxy. In different phrases, cosmic rays can come out of the galactic heart, however it is vitally troublesome to enter it.
How this cosmic barrier works, or why it exists, stays a thriller.
A monster within the center
The middle of our galaxy is positioned about 26,000 light-years from Earth within the constellation Sagittarius. It’s a dense and dusty place, containing greater than one million occasions extra stars per gentle 12 months than the complete photo voltaic system – all the pieces is wrapped round a supermassive black gap with about 4 million occasions the mass of the Solar.
Scientists have lengthy suspected that this black gap, known as Sagittarius A *, accelerates protons and electrons to a velocity near gentle, creating cosmic rays that propagate via our galaxy and additional into intergalactic area. These rays propagate via the magnetic fields of our galaxy, creating an ocean of high-energy particles whose density is roughly uniform all through the Milky Approach. This secure particle soup is named a sea of cosmic rays.
Of their new examine, the researchers in contrast the density of cosmic rays on this sea with the density of cosmic rays throughout the galactic heart. Cosmic rays can’t be seen immediately, however scientists can discover them in gamma-ray maps of the universe, which successfully present the place cosmic rays collided with different sorts of matter.
Utilizing knowledge from a large-area Fermi telescope, the group confirmed that one thing within the galactic heart actually acts as a large particle accelerator, emitting cosmic rays into the galaxy. Doable culprits embody Sagittarius A *, as black holes can theoretically throw out.
The map additionally revealed a mysterious “protect”, a transparent level the place the density of cosmic rays drops considerably on the sting of the galactic heart. The supply of this phenomenon is tougher to find out, the researchers mentioned, however it may contain the confusion of magnetic fields close to the dense core of our galaxy.
For instance, dense clouds of mud and gasoline close to the galactic heart may collapse, compressing the magnetic fields there and making a protect proof against cosmic rays, the group states in its work. Or possibly the stellar winds with numerous stars within the galactic heart are pushing again in the direction of the ocean of cosmic rays, simply because the photo voltaic wind does, writes Dwell Science, and stories Sputnik.
Additional analysis is required to seek out out precisely what is occurring within the weird depths of our galaxy.