Newfound Quasar Wins Title: “Most Distant In The Universe”

Published: February 18 2000

Category:Astronomy, Florida, Research, Sciences

GAINESVILLE — If Guinness had a Book of Cosmic Records, a newly discovered quasar in the constellation Cetus would certainly deserve prominent mention. Scientific readings show “RD J030117+002025″ easily skates past the previous record holder as one of the earliest known structures ever to form in the universe.

A team of astronomers from the University of Florida, NASA’s Jet Propulsion Laboratory and the University of California have identified the candidate after nights of deep imaging at the California Institute of Technology’s 5-meter Hale telescope at Palomar Observatory in California and at the National Science Foundation’s 4-meter Mayall telescope at Kitt Peak in Arizona. A spectral analysis of the quasar’s light was completed at the Keck Observatory in Hawaii.

“This quasar is extremely far away, which means observing it is like looking back in time to the earliest times in the universe,” said Richard Elston, a UF associate professor of astronomy and the UF member of the research team. “It takes light a long time to get here from something that far away, so there’s no doubt this is one of the first objects formed that anyone has ever seen.”

The findings will be presented in an upcoming issue of the Astrophysical Journal Letters.

Quasars are highly luminous bodies that were more common in the early universe. Packed into a volume roughly equal to our solar system, a quasar emits an astonishing amount of energy — up to 10,000 times that of the whole Milky Way galaxy. Scientists believe quasars get their fuel from super-massive black holes that spit out enormous amounts of energy as they consume surrounding matter.

A quasar’s red shift measures how fast the object is moving away from us as the universe expands. The faster it moves away, the more its light shifts to the red part of the spectrum, or toward longer wavelengths. As discovered by Edwin Hubble in the 1920s, the faster an object appears to move, the farther away it is, which is why red shift is a good indicator of cosmic distances.

High-red-shift quasars are vitally important to understanding one of the biggest mysteries confronting scientists: how the universe went from the smooth, uniformity of its youth to the clumpy, galaxy-strewn formations of today. Analyzing the spectrum of distant, high-red-shift quasars can be illuminating.

“It’s like turning on a flashlight at the edge of the universe because it allows you to study everything that has developed between us and the quasar,” said Daniel Stern, of the Jet Propulsion Laboratory, who played a key role in the discovery. “A quasar at this distance is especially advantageous. Since quasars are more luminous than distant galaxies, they act as much brighter flashlights for probing the matter between galaxies.”

At a red shift of 5.50, light traveling from this quasar has journeyed about 13 billion years to get here. That pushes the quasar’s existence back to a time when the universe was less than 8 percent of its current age and 275 times its current density. The universe has expanded by a factor of 6.5 since then.

Until recently, no one had discovered an object that came close to a red shift of 5.0. Even now, only a handful of distant galaxies and quasars can claim membership in the exclusive, high red shift club. Only two other quasars make the grade: one at a red shift of 5.0 and the previous record holder at a red shift of 5.03, both of which were discovered by the Sloan Digital Sky Survey.

“The odds against us finding a quasar at a red shift of 5.5 were fairly large, especially when you consider how small a portion of the sky we were observing –10 arcminutes by 10 arcminutes. To get an idea of how small that is, try holding a dime at arm’s length against the night sky — it’s roughly the size of FDR’s ear,” Stern said.

Elston said the team was sifting through “thousands” of objects when it came upon the quasar. “You would expect to find one eventually,” he said, “but we found this one quite quickly.”

High-red shift quasars are vitally important to understanding one of the biggest mysteries confronting scientists: how the universe went from the smooth, uniformity of its youth to the clumpy, galaxy-strewn formations we observe today. Analyzing the spectrum of distant, high-red shift quasars can be illuminating.

The new quasar also will shed light on how matter was distributed at earlier stages of cosmic history and will be useful for testing whether the universe was neutral or ionized at red shift 5.5.

The paper was written by Elston; Daniel Stern and Peter Eisenhardt of the Jet Propulsion Laboratory; Hyron Spinrad, Steve Dawson, and Adam Stanford of the University of California; and Andrew Bunker of Cambridge University.


Christopher Davis
Richard Elston

Category:Astronomy, Florida, Research, Sciences