In 2010, the Fermi Gamma Ray space telescope discovered two immense structures at the limits of our galaxy, two “bubbles”, one to the north and one to the south of our galaxy’s axis of rotation, attached to its center. more than a decade later finally we know what could cause these Fermi bubbles.
Gamma ray bubbles.
Some of the largest structures we know of in the Universe are invisible to the human eye, and even to many telescopes. That is why some of these structures can go unnoticed by hundreds of years of space observation. One of these examples are Fermi bubbles.
The Fermi bubbles in our galaxy are two sphere-shaped (or rather ellipsoidal) structures that extend along 25,000 light years (each) on the north and south sides of our galaxy. This means that, although most of the matter in our galaxy remains in a disk of about 50,000 light-years in radius, its size is actually much larger.
The bubbles themselves are regions that emit gamma raysthe most energetic form that light can acquire.
galactic winds.
Although we know their main features, we are still not sure how these structures came to be, but a recent study by a researcher at Tokyo Metropolitan University has shed some light on these enigmatic structures.
In an article recently published in the magazine Monthly Notices of the Royal Astronomical Society, Yukata Fujita gave an account of his analysis of these structures. Through computer simulations, he verified that the bubbles had been created by wind emanating from the center of our galaxy.
The definition of wind here would be something like streams of charged particles traveling at high speeds. As much as about 1,000 kilometers per second. These currents that remained active also over 10,000,000 years.
reverse shock.
The key to the discovery has been the temperature. In his simulations, Fujita verified that the interaction between winds emanating from the center of our galaxy and the halo of gas that surrounds it, an interaction that he describes as a “reverse shock”, was the only one that generated the observable temperature pattern in these bubbles.
Far from being a unique case.
Fermi bubbles would not be a phenomenon exclusive to our galaxy. There is some correspondence between the emanations observed in other galaxies and what we believe to have caused the huge bubble-like structures in our own. We have observed these emanations outside our galaxy, which tells us that they are possible in ours, but also that Fermi bubbles are possible elsewhere in the Universe.
observe what happens in other galaxies It can help us to better understand what happens in our own. Often taking a different perspective gives us additional information. Even with respect to objects that are thousands of light years away from us.
Images | NASA Goddard Space Flight Center, Tokyo Metropolitan University
