Statistical analysis of supermassive black holes suggests that the spin of the black hole may play a role in the generation of powerful high-speed jets blasting radio waves and other radiation across the Universe.
Black holes absorb light and all other forms of radiation, making them impossible to detect directly. But the effects of black holes, in particular accretion disks where matter is shredded and superheated as it spirals down into the black hole, can release enormous amounts of energy.
The accretion disks around supermassive black holes (black holes with masses millions of times that of the Sun) are some of the brightest objects in the Universe. These objects are called "quasi-stellar radio sources" or "quasars," but actually this is a misnomer; only about 10% of quasars emit strong radio waves.
We now know that "radio loud" quasars occur when a fraction of the matter in the accretion disk avoids the final fate of falling into the black hole and comes blasting back out into space in high-speed jets emitted from the poles of the black hole. But we still don't understand why jets form some times and not other times.
A team led by Dr. Andreas Schulze at the National Astronomical Observatory of Japan investigated the possibility that the spin of the supermassive black hole might play a role in determining if the high-speed jets form. Because black holes cannot be observed directly, Schulze's team instead measured emissions from oxygen ions [O III] around the black hole and accretion disk to determine the radiative efficiency; i.e. how much energy matter releases as it falls into the black hole. From the radiative efficiency they were able to calculate the spin of the black hole at the center.
By analyzing nearly 8000 quasars from the Sloan Digital Sky Survey, Schulze's team found that on average the O III oxygen emissions are 1.5 times stronger in radio loud quasars than in radio quiet quasars. This implies that spin is an important factor in the generation of jets.
Schulze cautions, "Our approach, like others, relies on a number of key assumptions. Our results certainly don't mean that spin must be the only factor for differentiation between radio-loud and radio-quiet quasars. The results do suggest, however, that we shouldn't count spin out of the game. It might be determining the loudness of these distant accreting monsters."
Hitoshi Yamaoka | EurekAlert!
Statistical inference to mimic the operating manner of highly-experienced crystallographer
18.09.2019 | Japan Science and Technology Agency
Scientists create fully electronic 2-dimensional spin transistors
18.09.2019 | University of Groningen
Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Hamburg and the European Molecular Biology Laboratory (EMBL) outstation in the city have developed a new method to watch biomolecules at work. This method dramatically simplifies starting enzymatic reactions by mixing a cocktail of small amounts of liquids with protein crystals. Determination of the protein structures at different times after mixing can be assembled into a time-lapse sequence that shows the molecular foundations of biology.
The functions of biomolecules are determined by their motions and structural changes. Yet it is a formidable challenge to understand these dynamic motions.
At the International Symposium on Automotive Lighting 2019 (ISAL) in Darmstadt from September 23 to 25, 2019, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, a provider of research and development services in the field of organic electronics, will present OLED light strips of any length with additional functionalities for the first time at booth no. 37.
Almost everyone is familiar with light strips for interior design. LED strips are available by the metre in DIY stores around the corner and are just as often...
Later during this century, around 2060, a paradigm shift in global energy consumption is expected: we will spend more energy for cooling than for heating....
Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Potsdam (both in Germany) and the University of Toronto (Canada) have pieced together a detailed time-lapse movie revealing all the major steps during the catalytic cycle of an enzyme. Surprisingly, the communication between the protein units is accomplished via a water-network akin to a string telephone. This communication is aligned with a ‘breathing’ motion, that is the expansion and contraction of the protein.
This time-lapse sequence of structures reveals dynamic motions as a fundamental element in the molecular foundations of biology.
Two research teams have succeeded simultaneously in measuring the long-sought Thorium nuclear transition, which enables extremely precise nuclear clocks. TU Wien (Vienna) is part of both teams.
If you want to build the most accurate clock in the world, you need something that "ticks" very fast and extremely precise. In an atomic clock, electrons are...
10.09.2019 | Event News
04.09.2019 | Event News
29.08.2019 | Event News
18.09.2019 | Innovative Products
18.09.2019 | Physics and Astronomy
18.09.2019 | Materials Sciences