Thanks to the VLT telescope, astronomers were able to make the most detailed observation to date of the orbital movement of hot gas near a supermassive black hole in the center of the Milky Way. The article was published in the journal Astronomy & Astrophysics. The work was briefly described on the website of the European Southern Observatory.
In the central region of the Milky Way, at a distance of 26,000 light years from the Sun, there is a compact radio source called Sagittarius A *, which presumably is a supermassive black hole with 4.2 million solar masses.
It is believed that the non-thermal radiation of Sagittarius A * is generated when the relativistic electrons move in a hot magnetized accretion disk surrounding a black hole, with a diameter of about ten light minutes, and in the region beyond the orbit more stable circular (ISCO) around a supermassive black hole, where matter can not move away from a black hole and inevitably falls beyond the event horizon.
The study of this area near a black hole, where relativistic accretion processes are carried out, provides important information about these mysterious objects and the physical processes associated with them.
Watching the movement of some “hot spots”
The task for the GRAVITY astronomers was to observe the orbital movement of “hot spots” of a relativistic gas in the innermost zone of accretion around a black hole. For the observations, the GRAVITY receiver was used, which collects light simultaneously from four telescopes of the VLT complex in Chile.
The scientists managed to register three bright flashes (July 22, July 28 and May 27, 2018) near the black hole. The following comparisons of the parameters of these bursts with computer models showed that they resemble “hot spots” formed due to magnetic perturbations in the hot gas moving in a circular orbit near a supermassive black hole.
“It’s amazing when you see in reality how matter revolves around a supermassive black hole at a speed of 30% of light. The amazing sensitivity of the GRAVITY receiver allowed us to observe the accretion process in real time with unprecedented detail, “said Oliver Pfuhl, a scientist at the Max Planck Institute for Extraterrestrial Physics, and one of the co-authors of the work.
In May, astronomers saw what they believe is the fastest growing black hole ever seen in the Universe, and in addition, it is voraciously hungry – it swallows the equivalent of our sun’s mass every two days.
The information was reviewed in a statement from the Australian National University (ANU), and research on the stellar object will be published in Publications of the Astronomical Society of Australia (PASA). In as much, you can see it in the web of pre-published works ArXiv.