Farsighted
Ohio State researchers look across the universe to quasars
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| A mosaic of X-ray images of the quasar Q2237+0305, magnified by a gravitational lens. The bright spots are four magnified images of the same quasar, which change in brightness over time. Mosaic courtesy of Ohio State University. |
Since radio telescopes first detected quasars in the 1950s, the objects--the brightest things in the universe and some of the furthest from Earth--have been something of a mystery to scientists.
But Ohio State researchers recently got the first look inside quasars. And they determined that the most recent theory is correct: Quasars are made up of massive black holes that are billions of years old.
"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."
Black holes' huge size makes their gravitational pull so strong that they yank in anything around them, even light, so they're impossible to observe directly. But as material is sucked into a black hole, it glows brightly. When material is pulled into a quasar, it emits visible light, radio waves, and X-rays.
Quasars are so far away that even in the most advanced telescopes, they look like a tiny pinpoint of light.
But when a galaxy lines up just right between the two quasars in the study and the Earth, the galaxy magnifies the quasars' light. That magnification made it possible for Dai and Christopher Kochanek, an astronomy professor, to look inside the quasars.
The result: A view as clear as if the scientists had been able to put the quasars under a microscope.
"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."
(Read the research news story by Pam Frost Gorder.)
Related links:
The Ohio State University Department of Astronomy
The Ohio State University College of Mathematical and Physical Sciences
