European Southern Observatory Imaging Survey; NOAO This color image shows the faint red galaxies of the galaxy cluster XMMXCS 2215-1738 in the center, along with the bluish haze which represents the invisible X-ray emission from the extremely hot gas that exists in between the cluster galaxies. Click photo for larger image.

A computer survey technique developed by Carnegie Mellon University researchers has led to discovery of the most distant galaxy cluster in the universe, and the most massive to date.

Known as XMM-XCS 2214-1734, the cluster contains hundreds of galaxies surrounded by superheated, X-ray-emitting gas whose temperature reaches more than 10 million degrees.

Through high-powered X-ray satellite images, the galaxy cluster looks like a fuzzy blue ball.

Discovery of "the fossil of the early universe," believed to be almost 10 billion years old, is generating excitement among cosmologists and astrophysicists as an astronomical treasure that could help define the parameters of the universe.

Kathy Romer, a lecturer in physics and astronomy at the University of Sussex in England and principal investigator of the XMM-XCS team, began the research project while she was adjunct professor at Carnegie Mellon from 1997 through 2003.

Her student, Kivanc Sabirli, who is now working on her doctorate at Carnegie Mellon, worked full time for four years writing software used to process X-ray satellite data that led to the "needle in a haystack" discovery of the galaxy cluster.

Seventeen researchers with expertise in cosmology, optics, X-rays and other specialties participated in the project.

The discovery was announced yesterday during the 208th American Astronomical Society meeting in Calgary, Alberta.

"We've got a lot of bragging rights with this," said Dr. Romer, who has returned to Sussex University but still holds a position at Carnegie Mellon to supervise research. "This is pushing in the direction of dark energy, which is a hot topic. These clusters will play an important role in figuring out answers to those questions."

She said Ms. Sabirli's research, done under her guidance, included "ups and downs and all sorts of mishaps."

"But in the end she pulled through," Dr. Romer said, giving Ms. Sabirli much of the credit for the research project's success.

Reached by e-mail, Ms. Sabirli's comment was: "We are all excited about this cluster."

A key question for researchers is to explain how such a large mass of galactic matter could coalesce so early in the history of the universe, said Robert Nichol, professor at the University of Portsmouth, United Kingdom, and co-author of the paper.

The universe is believed to be 13 billion years old, but it took stars, galaxies and clusters billion of years to form after the Big Bang.

Cosmologists still are looking for clues about what happened in those first few billion years, said Larry Marschall, deputy press secretary for the astronomical society.

The project's lead author, Dr. Adam Stanford of University of California, Davis, and the Lawrence Livermore National Laboratory, said the discovery represents "a challenge for our models of the way massive galaxies formed, and to our understanding of how such massive clusters could exist at a relatively early era in the universe."

The discovery does support growing evidence that mysterious dark energy is accelerating the expansion of the universe, Mr. Marschall said.

In her research, Ms. Sabirli determined the galaxy cluster is 500 trillion times the mass of the sun and is composed mostly of dark matter, which is believed to be the predominant matter in galaxies.

The team is working on a long-term program to locate more clusters with the help of telescopes worldwide. It hopes to use the Hubble Space Telescope to provide more detail about the recently discovered cluster.

Using the Carnegie Mellon survey technique, the team already has identified 1,000 other galaxy clusters.