. | . |
Alma finds a swirling, cool jet that reveals a growing, supermassive black hole by Staff Writers Gothenburg, Sweden (SPX) Jul 11, 2016
A Chalmers-led team of astronomers have used the Alma telescope to make the surprising discovery of a jet of cool, dense gas in the centre of a galaxy located 70 million light years from Earth. The jet, with its unusual, swirling structure, gives new clues to a long-standing astronomical mystery - how supermassive black holes grow. A team of astronomers led by Susanne Aalto, professor of radio astronomy at Chalmers, has used the Alma telescope (Atacama Large Millimeter/submillimeter Array) to observe a remarkable structure in the centre of the galaxy NGC 1377, located 70 million light years from Earth in the constellation Eridanus (the River). The results are presented in a paper published in the June 2016 issue of the journal Astronomy and Astrophysics. "We were curious about this galaxy because of its bright, dust-enshrouded centre. What we weren't expecting was this: a long, narrow jet streaming out from the galaxy nucleus", says Susanne Aalto. The observations with Alma reveal a jet which is 500 light years long and less than 60 light years across, travelling at speeds of at least 800 000 kilometres per hour (500 000 miles per hour). Most galaxies have a supermassive black hole in their centres; these black holes can have masses of between a few million to a billion solar masses. How they grew to be so massive is a long-standing mystery for scientists. A black hole's presence can be seen indirectly by telescopes when matter is falling into it - a process which astronomers call "accretion". Jets of fast-moving material are typical signatures that a black hole is growing by accreting matter. The jet in NGC 1377 reveals the presence of a supermassive black hole. But it has even more to tell us, explains Francesco Costagliola (Chalmers), co-author on the paper. "The jets we usually see emerging from galaxy nuclei are very narrow tubes of hot plasma. This jet is very different. Instead it's extremely cool, and its light comes from dense gas composed of molecules", he says. The jet has ejected molecular gas equivalent to two million times the mass of the Sun over a period of only around half a million years - a very short time in the life of a galaxy. During this short and dramatic phase in the galaxy's evolution, its central, supermassive black hole must have grown fast. "Black holes that cause powerful narrow jets can grow slowly by accreting hot plasma. The black hole in NGC1377, on the other hand, is on a diet of cold gas and dust, and can therefore grow - at least for now - at a much faster rate", explains team member Jay Gallagher (University of Wisconsin-Madison). The motion of the gas in the jet also surprised the astronomers. The measurements with Alma are consistent with a jet that is precessing - swirling outwards like water from a garden sprinkler. "The jet's unusual swirling could be due to an uneven flow of gas towards the central black hole. Another possibility is that the galaxy's centre contains two supermassive black holes in orbit around each other", says Sebastien Muller, Chalmers, also a member of the team. The discovery of the remarkable cool, swirling jet from the centre of this galaxy would have been impossible without Alma, concludes Susanne Aalto. "Alma's unique ability to detect and measure cold gas is revolutionising our understanding of galaxies and their central black holes. In NGC 1377 we're witnessing a transient stage in a galaxy's evolution which will help us understand the most rapid and important growth phases of supermassive black holes, and the life cycle of galaxies in the universe", she says. This research is presented in the article A precessing molecular jet signaling an obscured, growing supermassive black hole in NGC 1377, published in the June 2016 issue of Astronomy and Astrophysics.
Related Links Chalmers University of Technology Understanding Time and Space
|
|
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. |