Gas clouds swirling around a black hole form the heart of an extremely distant bright astronomical object


Optical image of the quasar 3C 273 (the shining object similar to a star in the center) obtained with the Hubble Space Telescope. It was the first quasar to be identified. Credit: NASA.

In 1963, astronomer Maarten Schmidt identified the first quasi-stellar object or "quasar", an extremely bright but distant object. He discovered that the simple quasar, the active nucleus of a distant galaxy known to astronomers as 3C 273, was 100 times brighter than all the stars of our Milky Way combined.

The international team of GRAVITY astronomers, including Professor Hagai Netzer of the School of Physics and Astronomy at Tel Aviv University, concluded that the clouds gas moving rapidly around a central black hole form the very core of this quasar. The results of the new research were published in Nature November 29.

The first measurement of the black hole mass inside 3C 273, using an older method, was performed at the Florence TAU observatory and George Wise in 2000, as part of the program. PhD. research conducted by Dr Shai Kaspi of TAU, then a student in Professor Netzer's group. This result has now been corroborated by the observations of GRAVITY.

The search is the first detailed observation outside of our galaxy of gas clouds swirling around a central black hole. According to the researchers, GRAVITY measurements will become the benchmark for measuring black hole masses in thousands of other quasars.

Take a closer look at a black hole

The GRAVITY instrument, located in Paranal, Chile, has unprecedented capabilities. It combines the collective area of ​​four telescopes to form a virtual telescope, called interferometer, 130 meters wide. The instrument can detect distant astronomical objects at an extremely high resolution.

"Quasars are among the most distant astronomical objects that can be observed," says Professor Netzer. "They also play a fundamental role in the history of the universe, because their evolution is intimately linked to the growth of galaxies.While almost all large galaxies have a huge black hole in their center, day, only one of our Milky Way has been accessible.These detailed studies. "

"GRAVITY has allowed us to solve, for the very first time, the movement of gas clouds around a central black hole," says Eckhard Sturm of the Max Planck Institute for Extraterrestrial Physics (MPE) , who led the research for the study. "Our observations can follow the movement of the gas and reveal that the clouds are spinning around the central black hole."

Until now, such observations have not been possible due to the small angular size of the inner region of a quasar – about the size of our solar system – but distant from 2 , 5 billion light years from us.

"The broad emission lines created by the gases near the black hole are marks of quasar observation." "Until now, the distance between the gas and the black hole, and occasionally the motive of movement, could only be measured by an older method that benefited from slight variations in the quasars, "Professor Netzer explains. "With the GRAVITY instrument, we can distinguish structures at the level of 10 microseconds, which corresponds to the observation, for example, of a 1 euro coin on the moon."

"Information on the movement and distance of gas immediately around the black hole is essential for measuring black hole mass," said Jason Dexter, also of MPE, who led the research. "For the first time, the old method has been experimentally tested and passed its test handily, confirming previous estimates of about 300 million solar masses for the black hole."

"This is the first time we can study the immediate vicinity of a huge black hole outside our home galaxy, the Milky Way," says Reinhard Genzel, head of the Infrared Research Group at MPE. "Black holes are intriguing objects, allowing us to probe physics under extreme conditions, and with GRAVITY we can now probe them from near and far."

Explore further:
Most detailed observations of equipment in orbit close to a black hole

More information:
Spatially resolved rotation of the region of wide lines of a quasar to a scale lower than parsec, Nature (2018). DOI: 10.1038 / s41586-018-0731-9

Journal reference:

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Tel Aviv University

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