Scientists at the University of Tübingen in Germany have solved the mystery of the origin of a giant, mysterious hourglass-shaped structure above and below the Milky Way, called “eROSITA bubbles” and visible in X-rays. They resemble Fermi bubbles, which emit higher frequency X-rays. The discovery is reported in an article published in the journal Nature.
The eROSITA bubbles are possibly evidence of the high activity of the supermassive black hole in the center of the galaxy, which has generated shock waves propagating through the hot gas. This structure was discovered by the eROSITA X-ray telescope, which recorded a huge accumulation of hot gas that occupies most of the sky in the southern hemisphere of the Earth. It was already known that such a space formation – the Northern Polar Spur – is in the sky of the Northern Hemisphere of the Earth. It was thought to be a supernova remnant, but it is now clear that it is part of a larger symmetric structure.
The eROSITA bubbles are 50,000 light-years across and are morphologically very similar to Fermi bubbles. They span 25,000 light-years each, lie on either side of the plane of the galaxy, and emit X-rays and gamma rays. The reason for their occurrence could be relativistic jets from a black hole, which was active 5-6 million years ago.
According to scientists, the formation of these structures requires an energy of 10 to the 56th power of erg, which is equivalent to the explosion of one hundred thousand supernovae or an explosion in the core of an active galaxy.