Most detailed observations of material orbiting close to a black hole

ESO's exquisitely sensitive GRAVITY instrument has added more evidence to the long-standing assumption that a supermassive black hole lurks in the center of the Milky Way. New observations show clumps of gas at about 30% of the speed of light on a circular orbit material orbiting this close to a black hole.

ESO's GRAVITY instrument on the Very Large Telescope (VLT) Interferometer has been used by scientists from a consortium of European institutions, including ESO, to observe the flares of infrared radiation from the accretion disc around Sagittarius A *, the massive object at the heart of the Milky Way. The observed flares provide long-awaited confirmation that the object in the center of the galaxy is assumed to have a supermassive black hole. The flares originate from the orbiting material, orbiting the horizon, orbiting the horizon.

While some matter in the accretion disc-the belt of gas orbiting Sagittarius A * at relativistic speeds-can orbit the black hole safely, anything that gets too close The closest point to a black hole that can be orbited by the huge mass orbit, and it is here that the observed flares originate.

"It's mind-boggling to actually witness material orbiting a massive black hole at 30% of the speed of light," marveled Oliver Pfuhl, a scientist at the MPE. "GRAVITY's tremendous sensitivity in the real world in unprecedented detail."

These measurements were only possible thanks to international collaboration and state-of-the-art instrumentation. The GRAVITY instrument which makes this work possible the telescopes of ESO's VLT to create a virtual super-telescope 130 meters in diameter, and has already been used to probe the nature of Sagittarius A *.

Earlier this year, GRAVITY and SINFONI, another instrument on the VLT, allowed the same team to accurately measure the S2 as it passed through the extreme gravitational field near Sagittarius A *, and for the first time revealed the effects predicted by Einstein's general relativity in such an extreme environment. During S2's close fly-by, strong infrared emission was also observed.

"We were closely monitoring S2, and we were always keeping an eye on Sagittarius A *," Pfuhl explained. "During our observations, we were lucky enough to notice three bright flares from around the black hole-it was a lucky coincidence!"

This issue, from highly energetic electrons to close the black hole, was visible as three prominent bright flares, and exactly matched predictions for hot spots orbiting close to a black hole of four million solar masses. The flares are thought to originate from magnetic interactions in the very hot gas orbiting very close to Sagittarius A *.

Reinhard Genzel, of the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany, explains: "This is one of our dream projects, but we hope it will be possible soon. " Referring to the long-standing assumption that Sagittarius A * is a supermassive black hole, Genzel concluded that "the result is a resounding confirmation of the massive black hole paradigm."

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More information:
"Detection of Orbital Motions Near the Last Stable Circular Orbit of the Massive Black Hole SgrA *", by the GRAVITY Collaboration, Astronomy & Astrophysics, 31 October 2018.