International team helps explain how black hole outflows affect structure formation in universe
An international team of scientists including a Virginia Tech physicist have discovered that winds blowing from a supermassive black hole in a nearby galaxy work to obscure observations and x-rays.
This is an illustration of the physical, spatial and temporal picture for the outflows emanating from the vicinity of the super massive black hole in the galaxy NGC 5548. The behavior of the emission source in five epochs is shown along the time axis. The obscurer is situated at roughly 0.03 light years (0.01 parsecs) from the emission source and is only seen in 2011 and 2013 (it is much stronger in 2013). Outflow component 1 shows the most dramatic changes in its absorption troughs. Different observed ionic species are represented as colored zones within the absorbers.
Credit: Ann Feild/Space Telescope Science Institute
The discovery in today's (June 19, 2004) issue of Science Express sheds light on the unexpected behavior of black holes, which emit large amounts of matter through powerful, galactic winds.
Using a large array of satellites and space observatories, the team spent more than a year training their instruments on the brightest and most studied of the "local" black holes — the one situated at the core of Type I Seyfert Galaxy NGC 5548.
What they found was a bit of a surprise.
The researchers discovered much colder gas than expected based on past observations, showing that the wind had cooled and that a stream of gas moved quickly outward and blocked 90 percent of x-rays. The observation was the first direct evidence of an obscuration process that — in more luminous galaxies — has been shown to regulate growth of black holes.
By looking at data from different sources, scientists found that a thick layer of gas lay between the galactic nucleus and the Earth blocked the lower energy x-rays often used to study the system, but allowed more energetic x-rays to get through.
Data from Hubble Space Telescope also showed ultraviolet emissions being partially absorbed by a stream of gas.
A multi-wavelength observational campaign simultaneously looking at an object to decipher its secrets is rare, the researchers said.
"I don't think anyone has trained so many scopes and put in so much time on a single object like this," said Nahum Arav, an associate professor of physics with Virginia Tech's College of Science. "The result is quite spectacular. We saw something that was never studied well before and we also deciphered the outflow in the object. We know far more about this outflow than any studied previously as to where it is and how it behaves in time. We have a physical model that explains all the data we've taken of the outflow over 16 years."
The discovery was made by an international team led by SRON Netherlands Institute for Space Research scientist Jelle Kaastra using the major space observatories of the European Space Agency, NASA, the Hubble Space Telescope, Swift, NuSTAR, Chandra, INTREGRAL, and other satellites and observation platforms.
"These outflows are thought to be a major player in the structure formation of the universe," Arav said "This particular outflow is comparatively small but because it's so close we can study it very well and then create a better understanding of how the phenomenon will work in very large objects that do affect the structure formation in the universe."
"Shadowing" of light from a black hole had not been seen before. With the discovery, scientists were able to decipher the outflow.
"Until now our knowledge of these characteristics was very limited," Arav said. "Before we were making educated inferences — but now we know. We know the distance of outflow from the center of source, we know the mass of outflow, and we know what causes its observed changes. The shadowing was definitely a surprise —a beautiful phenomenon we were lucky to catch."
Arav said luck played a part because the effect hadn't existed before last year.
Over the past two years the shadowing has built up and Arav believes it won't last much longer than another year or two, but concedes scientists don't have a full enough observation to say how the shadowing feature is changing in time.
Rosaire Bushey | Eurek Alert!
A New Litmus Test for Chaos?
29.07.2015 | American Institute of Physics (AIP)
First detection of lithium from an exploding star
29.07.2015 | ESO
Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.
Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight
A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...
Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.
By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...
Argonne scientists used Mira to identify and improve a new mechanism for eliminating friction, which fed into the development of a hybrid material that exhibited superlubricity at the macroscale for the first time. Argonne Leadership Computing Facility (ALCF) researchers helped enable the groundbreaking simulations by overcoming a performance bottleneck that doubled the speed of the team's code.
While reviewing the simulation results of a promising new lubricant material, Argonne researcher Sanket Deshmukh stumbled upon a phenomenon that had never been...
A NASA camera on the Deep Space Climate Observatory (DSCOVR) satellite has returned its first view of the entire sunlit side of Earth from one million miles away.
The color images of Earth from NASA's Earth Polychromatic Imaging Camera (EPIC) are generated by combining three separate images to create a...
23.07.2015 | Event News
10.07.2015 | Event News
25.06.2015 | Event News
29.07.2015 | Physics and Astronomy
29.07.2015 | Life Sciences
29.07.2015 | Awards Funding