The study lends further confirmation to what scientists have long suspected -- that quasars are made up of super-massive black holes and the super-heated disks of material that are spiraling into them.
The results of the Ohio State University-led project were reported Thursday at the meeting of the American Astronomical Society (AAS) High Energy Astrophysics Division in San Francisco.
"There are many models that try to describe what's happening inside a quasar, and before, none of them could be ruled out. Now some of them can," said Xinyu Dai, a postdoctoral researcher at Ohio State. "We can begin to make more precise models of quasars, and gain a more complete view of black holes."
Seen from Earth, quasars, or quasi-stellar objects, look like stars. They are extremely bright, which is why we can see them even though they are among the most distant objects in the universe. Astronomers puzzled over quasars for decades before deciding that they most likely contain super-massive black holes that formed billions of years ago.
Black holes cannot be directly observed, because they are so massive that even light cannot escape their gravity. The material that is falling into a black hole, on the other hand, glows brightly. In the case of quasars, the material shines across a broad range of energies, including visible light, radio waves, and X-rays.
Dai and Christopher Kochanek, professor of astronomy, and their colleagues studied the light emanating from two quasars.
Quasars are so far away that even in the most advanced telescopes, they look like a tiny pinpoint of light. The interior structures of the two quasars in this study only became visible when a galaxy happened to line up just right between them and the Earth, and magnified their light like a lens.
The astronomers likened the effect to being able to look at the quasars under a microscope.
Einstein predicted that massive objects in space can sometimes act like lenses, bending and magnifying light from objects that are behind them, as seen by an observer. The effect is called gravitational lensing, and it enables astronomers to study some objects in otherwise unattainable detail.
"Luckily for us, sometimes stars and galaxies act as very high-resolution telescopes," Kochanek said. "Now we're not just looking at a quasar, we're probing the very inside of a quasar and getting down to where the black hole is."
They were able to measure the size of the so-called accretion disk around the black hole inside each quasar.
In each, the disk surrounded a smaller area that was emitting X-rays, as if the disk material was being heated up as it fell into the black hole in the center.
That's what they expected to see, given current notions about quasars. But the inside view will help them begin to refine those notions, Dai said.
Key to the project was NASA's Chandra X-Ray Observatory, which allowed them to precisely measure the brightness of the X-ray emitting region of each quasar. They coupled those measurements to ones from optical telescopes which belong to the Small and Moderate Aperture Research Telescope System Consortium.
The astronomers studied the variability of both the X-rays and visible light coming from the quasars and compared those measurements to calculate the size of the accretion disk in each. They used a computer program that Kochanek created especially for such calculations, and ran it on a 48-processor computer cluster. Calculations for each quasar took about a week to complete.
The two quasars they studied are named RXJ1131-1231 and Q2237+0305, and there's nothing special about them, Kochanek said, except that they were both gravitationally lensed. He and his group are currently studying 20 such lensed quasars, and they'd like to eventually gather X-ray data on all of them.
This project is part of an ongoing collaboration between Ohio State and Penn State University. Coauthors on the AAS presentation included Nicholas Morgan of Ohio State, and George Chartas and Gordon Garmire of Penn State.
NASA funded this research. The computer cluster was provided by Cluster Ohio, an initiative of the Ohio Supercomputer Center (OSC), the Ohio Board of Regents, and the OSC Statewide Users Group.
Astronomers release most complete ultraviolet-light survey of nearby galaxies
18.05.2018 | NASA/Goddard Space Flight Center
A quantum entanglement between two physically separated ultra-cold atomic clouds
17.05.2018 | University of the Basque Country
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology