Two Penn State astronomers played important roles in the recent discovery of the most distant quasar ever found.

Donald Schneider, professor of astronomy and astrophysics, and Niel Brandt, associate professor of astronomy, both made key contributions to the discovery of three new quasars, one of which is the most distant quasar yet discovered.

Quasars are galaxies with super-massive black holes in the center, Brandt said.

They are "extremely luminous objects, up to 1,000 times more luminous than our galaxy in a space the size of our solar system," a fact that Schneider said was astonishing.

Because these objects are so distant, and because light does not travel instantaneously, the light they give off takes millions or billions of years to reach us, Schneider said. This means that radiation that appears as if it is being emitted from the new quasar now actually began its journey to Earth a mere 800 million years after the formation of the universe.

Studying extremely distant objects allows scientists to examine the universe at a younger time, Schneider said.

Quasars in particular are useful in this way, because their brightness allows researchers to view them at very great distances, he added.

The discovery of the new quasars was the product of the work of the Sloan Digital Sky Survey. This project's ultimate goal is "to map in detail one quarter of the entire sky, including the position and brightness of over 100 million objects," said Gary Ruderman, spokesman for the Sloan Survey.

The project is the joint work of 13 educational institutions and involves over 100 astronomers, Ruderman said. It has been operating since about 1994, and recorded its first images in 1998.

One of the survey's chief areas of focus is the study of quasars, Schneider said.

Schneider has been with the Sloan Survey for about 10 years and is currently the chairman of the Quasar Science Working Group.

Brandt's contribution to the discovery of the new quasars was in the area of X-ray astronomy, the study of cosmic sources of radiation.

"We know that super-massive black holes are copious producers of X-rays," Brandt said.

The fact that black holes produce so much X-ray radiation helps astronomers target and identify quasars.

Astronomers working on the survey were aided in their discovery of the new quasars by the 9.2-meter Hobby-Eberly telescope, of which Penn State is a partial owner, Schneider said.

The telescope helped astronomers identify actual quasars from among a group of candidate quasars, which had been identified previously using other instruments.