. | . |
A Close-up Look at the Whirlpool Around a Gigantic Black Hole by Staff Writers Garching, Germany (SPX) Nov 30, 2018
Detailed observations of the quasar 3C 273 with the GRAVITY instrument reveal the structure of rapidly moving gas around the central super-massive black hole, the first time that the so-called "broad line region" could be resolved. The international team of astronomers was thus able to measure the mass of the black hole with unprecedented precision. This measurement confirms the fundamental assumptions of the most commonly used method to measure the mass of central black holes in distant quasars. Studying these black holes and determining their masses is an essential ingredient to understanding galaxy evolution in general. More than 50 years ago, the astronomer Maarten Schmidt identified the first "quasi-stellar object" or quasar, named 3C 273, as an extremely bright but distant object. The energy emitted by such a quasar is much greater than in a normal galaxy such as our Milky Way and cannot be produced by regular fusion processes in stars. Instead, astronomers assume that gravitational energy is converted into heat as material is being swallowed by an extremely massive black hole. An international team of astronomers has now used the GRAVITY instrument to look deep into the heart of the quasar and was able to actually observe the structure of rapidly moving gas around the central black hole. So far, such observations had not been possible due to the small angular size of this inner region, which is about the size of our solar system but at a distance of some 2.5 billion light-years. The GRAVITY instrument combines all four ESO VLT telescopes in a technique called interferometry, which allows a huge gain in angular resolution, equivalent to a telescope with 130 metres in diameter. Thus the astronomers can reveal structures at the level of 10 micro-arcseconds, which corresponds to about 0.1 light-year at the distance of the quasar (or an object the size of a 1-Euro-coin on the Moon). "GRAVITY allowed us to resolve the so-called 'broad line region' for the first time ever, and to observe the motion of gas clouds around the central black hole," explains Eckhard Sturm, lead author from the Max Planck Institute for Extraterrestrial Physics (MPE). "Our observations reveal that the gas clouds do whirl around the central black hole." The broad atomic emission lines are an observational hallmark of quasars, clearly indicating the extra-galactic origin of the source. So far, the size of the broad line region is measured mainly by a method called "reverberation mapping." Brightness variations of the quasar's central engine cause a light echo once the radiation hits clouds further out - the larger the size of the system, the later the echo. In the best cases, the motions of the gas can also be identified, often implying a disk in rotation. This result, derived from timing information, can now be confronted with spatially resolved observations with GRAVITY. "Our results support the fundamental assumptions of reverberation mapping," confirms Jason Dexter, co-lead author from MPE. "Information about the motion and size of the region immediately around the black hole are crucial to measure its mass," he adds. For the first time, the method was now tested experimentally and passed its test with flying colours, confirming previous mass estimates of about 300 million solar masses for the black hole. Thus, GRAVITY provides both a confirmation of the main method used previously to determine black hole masses in quasars and a new and highly accurate, independent method to measure such masses. It thereby promises to provide a benchmark for measuring black hole masses in thousands of other quasars. Quasars play a fundamental role in the history of the universe, as their evolution is intricately tied to galaxy growth. While astronomers assume that basically all large galaxies harbour a massive black hole at their centre, so far only the one in our Milky Way has been accessible for detailed studies. "This is the first time that we can spatially resolve and study the immediate environs of a massive black hole outside our home galaxy, the Milky Way," emphasizes 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 both near and far."
Research Report: "Spatially Resolved Rotation of the Broad-Line Region of a Quasar at Sub-Parsec Scale," GRAVITY Collaboration: E. Sturm, J. Dexter, O.Pfuhl, M. R. Stock et al., 2018 Nov. 28, Nature
Researchers have created a virtual reality simulation of a supermassive black hole Washington DC (SPX) Nov 26, 2018 The black hole at the centre of our galaxy, Sagittarius A*, has been visualised in virtual reality for the first time. The details are described in an article published in the open access journal Computational Astrophysics and Cosmology. Scientists at Radboud University, The Netherlands and Goethe University, Germany used recent astrophysical models of Sagittarius A* to create a series of images that were then put together to create a 360 degree virtual reality simulation of the black hole, that c ... read more
|
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |