SRON Netherlands Institute for Space Research

Our mission is to bring about breakthroughs in international space research

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SRON Netherlands Institute for Space Research

SRON Netherlands Institute for Space Research

SRON Netherlands Institute for Space Research

Our mission is to bring about breakthroughs in international space research

SEE MORE

SRON Netherlands Institute for Space Research

LATEST NEWS

An international team of astrophysicists has established that supermassive black holes behave like small stellar black holes. They made their discovery by observing a supermassive black hole that has torn apart a star, causing a surge of gas towards it. Normally such a change in the gas flow takes too long to detect. But this time the transition from a steady flow to a surge of gas happened abruptly, enabling the researchers to detect a jet blasting from the supermassive black hole. This neatly fits the pattern found near small black holes. The results appear 26 November in Science.

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Artist's impression of a black hole with a jet (University of Warwick / Mark A. Garlick)

Gas flows are often found nearby black holes. Many supermassive black holes are fed by a steady diet of gas, leading to gas flows that live for millions of years and change little on a human timescale. But the newly discovered black hole gas flow behaved very differently: the observations show that following the injection of gas, the supermassive black hole produced a short but spectacular radio flare. The astrophysicists discovered that this radio flare originates from a jet blasting matter from the supermassive black hole at nearly the speed of light. They also observed a burst of X-rays and optical light. This follows the pattern found in small stellar-mass black holes.

Rapid response
The discovery of this radio flare was made possible by a rapid observational response after the stellar disruption (known as ASAS-SN-14li) was announced in December 2014. "Previous efforts to find evidence for these escaping jets, including my own, were too late to the game," says Sjoert van Velzen, postdoctoral fellow at Johns Hopkins University, lead-author of the Science paper. Co-author Thomas Wevers (Radboud University and SRON) adds: "These earlier attempts all involved events that happened far away, while we now were the first to get front row seats for the action." In this branch of astronomy, the front row means a distance of 300 million light years, while the previous observations were based on events at least three times farther away.

Matryoshka dolls

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Artist's impression of an active black hole (NASA/Goddard Space Flight Center/Swift)

The observed jet was anticipated by the so-called scale-invariant model of accretion, also known as the Matryoshka-doll theory of astrophysics. It predicts that all compact astrophysical objects that accrete matter (e.g. from stellar-mass black holes to super-massive black holes) behave and look the same after a simple correction based on solely the mass of the object. In other words, the larger Matryoshka doll (a supermassive black hole, millions to billions times as massive as the Sun) is just a scaled-up version of the smaller doll (a stellar-mass black hole that has a mass of around ten times that of the Sun). Since stellar-mass black holes consistently produce a radio-emitting jet when they are supplied with a large amount of gas, the theory predicts that supermassive black holes should do the same when they swallow a star. "I always liked the elegant nature of the scale-invariant theory," says co-author Peter Jonker (SRON/Radboud Universiteit). "But previous observations never found evidence for the jet it predicted. Our new findings suggest that this new type of jet could indeed be common. Previous observations were simply not sensitive enough to detect them." Thus, the study concludes by hypothesizing that every stellar disruption leads to a radio flare similar to the one just discovered. Finding more of these rare events may further improve our understanding of the processes that allow black holes to launch such spectacular jets.

More information
For their observations the astrophysicists used the AMI radio telescope array, the Westerbork radio telescope array and the Swift X-ray satellite. The paper A radio jet from the optical and X-ray bright stellar tidal disruption flare ASASSN-14li will be published online 26 November in Science. Authors are: Sjoert van Velzen (Johns Hopkins University), Thomas Wevers (Radboud University/SRON), Peter Jonker (SRON/Radboud University), G. E. Anderson (University of Oxford, Curtin University), N. C. Stone en B. D. Metzger (University of Columbia), M. Fraser, S. T. Hodgkin en H. C. Campbell (University of Cambridge), A. J. van der Horst (George Washington University), T. D. Staley (University of Oxford), A. J. Mendez (Johns Hopkins University), J. C. A. Miller-Jones (Curtin University), en R. P. Fender (University of Oxford).

RESEARCH

SRON has four programme lines, Astrophysics, ExoplanetsEarth, and Technology, with science groups attached, and two expertise groups, Instrument science and Engineering.

ASTROPHYSICS

The Astrophysics programme at SRON is dedicated to unraveling the history of the universe, from the first stars and black holes to large-scale structure.

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EXOPLANETS

The Exoplanets programme is dedicated to atmospheres of planets beyond our solar system and is an in-between of SRON's Astrophysics and Earth programmes.

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EARTH

The Earth programme is aimed at the climate and air quality of planet Earth, with focus on the global carbon cycle and aerosols.

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ENGINEERING

The Engineering group covers SRON's skills and know-how with regard to product assurance, quality assurance, configuration control, design engineering – electronic & mechanical – and parts procurement. It is an expertise group that provides resources for all SRON instrument projects.

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INSTRUMENT SCIENCE

The Instrument science group covers SRON's skills and know-how with regard to instrument physics, system engineering (up to full-instrument level) and project management. It is an expertise group that provides resources for all SRON instrument projects.

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TECHNOLOGY

The Technology programme is SRON's backbone for the development of enabling technology.

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SRON’s mission is to bring about breakthroughs in international space research 

Therefore the institute develops pioneering technology and advanced space instruments, and uses them to pursue fundamental astrophysical research, Earth science and exoplanetary research. As national expertise institute SRON gives counsel to the Dutch government and coordinates - from a science standpoint - national contributions to international space missions. SRON stimulates the implementation of space science in our society.



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