(ORDO NEWS) — In the strange gravitational environment at the center of our galaxy, astronomers have discovered a clump of gas orbiting a supermassive black hole at fantastic speeds.
The characteristics of this blob will help astronomers explore the space immediately surrounding Sagittarius A* in search of answers to the question of why the galactic center flickers and flashes across the entire electromagnetic spectrum.
The results of the study show that the black hole is surrounded by a clockwise rotating disk of material modulated by a powerful magnetic field. It also confirmed what we already knew: the space around the black hole is becoming anomalous.
“We think we’re looking at a hot gas bubble zipping around Sagittarius A* in an orbit similar in size to the planet Mercury, but completing a complete rotation in just 70 minutes,” said astrophysicist Maciek Wilgus of Max. Institute of Radio Astronomy.
Planck in Germany. According to him, this requires breathtaking speed – about 30% of the speed of light!
Earlier this year, Sagittarius A* (foreign designation – Sgr A*) was in the spotlight when the Event Horizon Telescope collaboration presented an image of a black hole that has been created for years.
Telescopes around the world worked together to make observations of the galactic center, which together revealed a donut-shaped ring of matter orbiting Sgr A* and heated to incredible temperatures.
One of the telescopes included in the collaboration is the Atacama Large Millimeter/Submillimeter Array (ALMA), a radio telescope array located in Chile’s Atacama Desert.
While studying the data exclusively from ALMA, in isolation from the rest of the collaboration, Vilgus and his colleagues noticed something interesting.
Emission from black holes
In April 2017, in the midst of data collection, the galactic center “spit out” an X-ray flare. It was pure coincidence when astronomers were collecting data for the Event Horizon Telescope project.
Previously, these long flares, observed at other wavelengths, have been associated with clumps of hot gas that orbit very close to the black hole and move at very high speeds.
“What is really new and interesting is the fact that such flares have so far only been clearly present in X-ray and infrared observations of Sagittarius A*.
Here, for the first time, we see a very strong indication that orbital hotspots are also present in radio observations, ” said Vilgus.
These flashes are believed to be the result of hot gas interacting with a magnetic field, and the team’s analysis of the ALMA data supports this notion.
The hotspot emits highly polarized or curved light and shows signs of synchrotron acceleration, both of which occur in the presence of a strong magnetic field.
And the glow in the radio light could be the result of the hot spot cooling after the flash and becoming visible at longer wavelengths.
The team’s analysis of the light suggests that the hotspot is embedded in a magnetically latched disc. This is a hot substance that rotates around the black hole and falls into it, but at a speed that is hindered by the magnetic field.
Through modeling that combined the data, the team was able to provide tighter constraints on the shape and movement of this magnetic field, and on the formation and evolution of a hotspot within it.
But we don’t know much yet. Studying black holes is extremely difficult, and there are still some strange inconsistencies compared to infrared observations of other flares.
The team hopes that simultaneous infrared and radio observations of future hotspot events will help smooth out these kinks.
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