February 19, 2013
Outflow From An Active Galactic Nucleus Imaged In 3D
Lee Rannals for redOrbit.com - Your Universe Online
The team used the large telescope to observe quasar SDSS J1029+2623, which sits 10 billion light-years away from Earth in the constellation Leo. By using the gravitational lensing technique, astronomers were able to look at this far away object at different angles.
When using gravitational lensing, light from SDSS J1029+2623 is bent around an intervening cluster, 5 billion light-years away from Earth, which allowed the team to see a more highly resolved and brighter image of the quasar.
Astronomers looked at multiple sight lines to create the 3D view of the quasar, providing a unique view into SDSS J1029+2623.
Quasars have a luminosity that can be hundreds of times greater than those of their host galaxies. Scientists think their light source is a bright gaseous disk surrounding a supermassive black hole at the center of the galaxy. Gas streams, known as "outflows," influence surrounding interstellar regions.
Results from the 3D images support the idea the sight lines are going through different areas of the outflow from different directions.
Despite the small separation angle in the image, one researcher on the project said the outflow may not necessarily be homogenous, but could have a complex internal structure with a number of clumpy gas clouds like cirrocumulus clouds in Earth's atmosphere.
Direct observations of a clumpy structure in tandem with theoretical analysis will help contribute to revealing the mysterious formation history of these outflows, according to the team.
They have also looked at other explanations for the outflows seen in the 3D images. These light paths have a time difference between them by the time they reach Earth. So, if the structure of the outflow varies with time, the two images deliver information about different epochs, even if they pass through the same region of the outflow.
Astronomers have said before they could use light of quasars to help map out the spread and structure of the universe. One team wrote in the Physical Review Letters they have developed a technique that could help look back into the universe's infancy.
They said by measuring the rate at which a quasar's light appears to vary, and comparing this rate to the standard rate, astronomers can determine the redshift of the quasar. Knowing this helps scientists calculate the relative size of the universe when the light was emitted, compared to today.
Larger samples of quasars could help confirm that the patterns are consistent, and could be used to calculate their redshifts everywhere in the universe.
“This could help us learn about how gravity has assembled structure in the universe.” Glenn Starkman, a physics professor at Case Western Reserve University, said in a statement. “And, the rate of structure growth can help us determine whether dark energy or modified laws of gravity drive the accelerated expansion of the universe.”