Astronomy & Astrophysics: hot gas bubble discovered near black hole Sagittarius A*
Astronomers have discovered a bubble of hot gas that orbits Sagittarius A*, the black hole at the center of the Milky Way. This is reported in an article published in the journal Astronomy & Astrophysics.
The researchers made observations using the ALMA radio telescope in Chile. The gas bubble’s orbit is roughly the size of Mercury’s, and the object itself orbits the black hole in about 70 minutes. At the same time, its speed reaches about 30 percent of the speed of light.
The discovery was made after NASA’s Chandra space telescope spotted an X-ray flare at the center of the Milky Way. Such flares have been observed exclusively in the X-ray and infrared range, and it is believed that they are manifestations of the same astrophysical process. When a hot object cools, it becomes visible at longer wavelengths of electromagnetic radiation, including in the radio range. As a result, the gas bubble became visible to ALMA.
Flares have long been thought to be due to magnetic interactions in a very hot gas orbiting very close to Sagittarius A*, and new evidence supports this idea. Scientists hope that they will be able to directly observe the clumps of gas in orbit around a black hole using the EHT (Event Horizon Telescope).