Xinyu Dai describes 1st look inside a quasar

Photo Credit: Ohio State University

Astronomers say there’s nothing special about two qusars – named RXJ1131-1231 and Q2237+0305 – except that a massive galaxy lies between them and us. The intervening galaxy acts as a lens to magnify the quasars’ structure. Astronomer Xinyu Dai at Ohio State University and his colleagues have managed a first glimpse inside a quasar. Xinyu Dai told EarthSky:

Quasars are objects that are very far away. Because they are so far away, when we look at them far away, directly, by imaging, they all look like little dots.

Quasars are distant, but we see them because they’re bright. The brightest one shines some two trillion times more powerfully than our sun. Astronomers believe that a quasar’s tremendous brightness stems from a central black hole. They think space dust and gas are sucked into the hole at close to the speed of light. This debris flares up and creates the brilliant light of quasars. Xinyu Dai told EarthSky about measuring the size of the disk of debris – what’s called the accretion disk – surrounding a black hole inside two quasars. He said:

The quasar has structure in it, and we couldn’t know that before. Now we can actually map the structure of quasar accretion discs.

Dai said both disks measure about 10 astronomical units in width, about 10 times the Earth-sun distance. In contrast, the quasars themselves are about a million billion astronomical units from Earth. He said that, before this research, there were many models that tried to describe what is happening inside a quasar. Before, none of them could be ruled out. Now some of them can.

The fact is that quasars are billions of miles away, so far away that even in the most advanced telescopes, they look like a tiny pinpoint of light. These astronomers used the fact that a massive galaxy lies between us and the quasars they studied. The intervening galaxy magnified the light like a lens, in an effect known as gravitational lensing. The astronomers likened the effect to being able to look at the quasars under a microscope.

Bottom line: Astronomer Xinyu Dai used gravitational lensing to get a glimpse inside the quasars RXJ1131-1231 and Q2237+0305.

Via Ohio State University

December 17, 2006

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