ASTRONOMERS DISCOVER POSSIBLE QUASAR IN MILKY WAY GALAXY

Soon after an x-ray burst was observed with the
Gamma-Ray Observatory (GRO)
radio VLBI
observations of GROJ1655-40 revealed evidence of rapid plasma jet
ejection. These properties are typical of quasars, and serve as mounting
evidence that quasars aren't extra-galactic as most cosmologists would
have us believe.

The strange behavior of a newly discovered star in the
Milky Way galaxy as it spewed out huge jets of material at
nearly the speed of light has led an international team of
radio astronomers to believe it may be a black hole or
neutron star powering a miniature quasar.

The star, identified as GRO J1655-40, was discovered using
NASA's Gamma Ray Observatory on July 27, 1994, when it
underwent such a strong outburst of x-rays that it quickly
became the strongest x-ray source in the sky, said Jet
Propulsion Laboratory astronomer Dr. Robert Preston, a
member of the observing team which began tracking the object
shortly after its discovery.

"The star exhibited some exotic behavior," Preston
said, "ejecting material at 80 percent of the speed of light
just like very powerful quasars. This suggests that the
object is likely to be powered by a black hole or neutron
star."

Black holes are thought to occur at the end of the
lifetime of a massive star, when the outward pressure of the
star's diminishing radiation can no longer prevent the
gravitational collapse of the star into a vanishingly small
volume. Quasars are believed to contain enormous black holes
with masses of up to billions of times that of the Sun.
A neutron star is a less dense form of a collapsed old star,
but still has a density of more than a billion tons per
teaspoon of material.

The discovery represents only the
second time that such
an object has been found in Earth's own galactic
neighborhood. The observations were made possible by a
technique called interferometry, in which several radio
telescopes are used simultaneously to synthesize one
enormous telescope.

The extremely energetic star was estimated to be about
12,000 light-years from Earth, or about 15 percent of the
way across the Milky Way galaxy, said Preston, whose
findings appeared in this week's issue of the science
journal Nature.

The team believes that the collapsed star -- observed
in the radio portion of the electromagnetic spectrum -- is
not a single star but rather two stars in orbit about each
other. They speculate that material may have been drawn off
one of the stars to form a disc that spiraled into the other
star, which is probably a black hole or neutron star.

Their radio observations, surprisingly, revealed that
the ejection of matter from the star did not start until 12
days after the beginning of the violent x-ray outburst.

"The enormous outburst could be caused by an unusually
large piece of the companion star falling onto the compact
star, with the subsequent expansion of the jets of matter
being ejected perpendicularly from the center of the disc,"
Preston said. "The influx of material was so great during
the x-ray outburst that it may have disrupted the production
of jets, thus causing the observed delay in the formation of
jets until the flow of material had diminished."

The fact that radio jets did not emerge until x-ray
emissions had subsided may be an important clue to the
nature of jet production, not only in similar objects but
also in the much more luminous and massive objects found in
distant quasars at the edge of the universe, the team
reported.

"Since quasars are found at distances of up to almost a
million times farther away than this x-ray star, astronomers
now have an opportunity to study a similar process in much
greater detail," Preston and his colleagues said.

The team of radio astronomers reporting this discovery
were from the
Jet Propulsion Laboratory
and several other institutions in
Australia
and South Africa. Their
observations were made using an array of radio telescopes
located at various sites across the world, including
telescopes at
NASA's Deep Space Network
in both California and Australia.

The research were sponsored in part by the Astrophysics
Division of NASA's Office of Space Science, Washington, D.C.