A scientist from Tokyo Metropolitan University has shown that large gamma-ray-emitting bubbles round the center of the Milky Way were produced by fast, outward-blowing winds and an connected “ reverse shock. ”
Numerical simulations successfully produced the temperature profile observed by an X-ray telescope. Such outflows have been noticed in other galaxies; this locating suggests similar winds may have been blowing in our own galaxy until quite recently.
The universe is full of massive celestial items that are yet to be explained. Among these are the “ Fermi bubbles, ” alleged because they were first uncovered by the Fermi Gamma-ray Room Telescope in 2010.
These bubbles are enormous gamma-ray-emitting regions that will extend from either part of the center of the Milky Way over approximately 50, 000 light yrs , protruding out from the aircraft of the galaxy like balloons as shown in the physique above. Despite their mind-blowing scale, the mechanism through which they are formed are yet to be deciphered.
Now, Professor Yutaka Fujita from Tokyo Metropolitan College has presented theoretical evidence demonstrating how such items may have been formed.
Since their breakthrough, many hypotheses have been submit about the formation of the Fermi bubbles, including explosive process of the central supermassive dark hole, winds from the dark hole, and steady star-formation activity.
Distinguishing these scenarios is a challenging task, but the availability of state-of-the-art X-ray observations from the Suzaku satellite offers a opportunity to compare measurements with what astronomers expect from various situations.
The simulations of Professor Fujita considered fast outflowing winds through the black hole injecting the necessary energy into the gas around the center of the galaxy.
Comparing with all the measured profiles, they discovered that there was a good opportunity that the Fermi bubbles are usually produced by the fast outflowing winds, blowing at one, 000 km per 2nd over 10 million years. These are not winds even as we would experience them in the world, but streams of extremely charged particles traveling on high speeds and propagating through space.
These winds travel outward and interact with surrounding halo gas, causing a reverse shock that creates a feature temperature peak. The Fermi bubbles correspond to the volume on the inside of this reverse shock front.
Importantly, simulations also showed that an instantaneous explosion at the middle could not reproduce the profiles measured by the telescope, lending weight to a scenario depending on steady winds generated with the central black hole.
The author notes the winds predicted by the simulation are similar to outflows observed in additional galaxies. The correspondence suggests the same kinds of massive outflows seen in other parts of the world were present in our own universe until fairly recently.