The eROSITA telescope discovered in 2019 a gigantic pair of X-radiation-emitting bubbles, each about 36.000 light-years tall and 45.600 light-years wide, above and below the center of our Milky Way galaxy. These bubbles were curiously very similar to two others found by another gamma-ray observatory, Fermi, a decade earlier. Somewhat smaller, they seemed to be swallowed.
What could have caused these two pairs of giants has until now been a mystery. But their similarities in size and shape suggest that they must have been ejected by the same cataclysmic event, some terrifying power of energy erupting from the core of our galaxy. a new study
published in 'Nature Astronomy' by an international team suggests that the bubbles are the result of a powerful jet of energy produced by Sagittarius A*, the supermassive black hole at the center of the Milky Way. It began to shed material about 2,6 million years ago and appeared about 100.000.
“Our conclusions are important in the sense that it is necessary to understand how the black magicians interact with the galaxies in the area you are in, because this interaction allows these black magicians to create a controlled form in the light of [growing] uncontrollably” says Mateusz Ruszkowski, an astronomer at the University of Michigan and a co-author of the study.
There are two competing models that explain Fermi and eRosita bubbles. The first suggests that the outflow is driven by a nuclear outburst, in which a star explodes into a supernova and expels material. The second model, which the team's findings support, suggests that these outflows are driven by energy ejected from the supermassive black hole at the center of our galaxy.
past active
Black holes are singular objects, so massive that not even light can escape. However, when black holes 'fill up' with material from their surroundings, they can create pairs of high-energy jets of matter that shoot in opposite directions at relativistic speeds, a significant fraction of the speed of light. According to the model made by astronomers, these very powerful jets lasted around 100.000 years. It engulfed up to 10,000 times the mass of the Sun during this time.
Astronomers are interested in observing these bubbles because they occur in our own galactic backyard as opposed to objects in a different galaxy or at an extreme cosmological distance. The existence of the bubbles indicates that Sagittarius A* had a much more active past compared to its current apparent calm. These activities give researchers valuable information about how the supermassive black hole and the galaxy grew to their current sizes. The findings can also be used to find out if there are similar bubbles in other galaxies.
