Sarah Keegan
Headquarters, Washington, D.C.                                         

September 21, 1994
(Phone:  202/358-1547)

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.
(Phone:  301/286-6256)

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
(Phone:  410/338-4514)

RELEASE:  94-160

HUBBLE UNCOVERS A HIDDEN QUASAR IN A NEARBY GALAXY

     Astronomers using NASA's Hubble Space Telescope have found a
new quasar -- not billions of light years away like its known cousins,
but a mere 600 million light years, the equivalent of Earth's cosmic
backyard.

     "I was stunned when we realized we had a quasar; it was a
total surprise," said Dr. Anne Kinney of the Space Telescope Science
Institute, Baltimore, Md.  Until this discovery all known quasars
existed in the early universe.  "So it is unusual to find one in our
own epoch," Dr. Kinney said.

     The discovery in galaxy Cygnus A will give astronomers their
first opportunity for detailed study of a quasar, an object which
looks like a pinpoint of light (as does a star) to a ground-based
telescope.  A quasar, though, emits hundreds of times more energy than
an entire galaxy with more than 100 billion stars.

     There is evidence that the quasars -- short for "quasi-stellar
radio sources" -- found in the remote galaxies are powered by
supermassive black holes that devour dust, gas and stars from the host
galaxies, producing enormous amounts of energy in the process.  Beyond
that, little is known about them, which makes this discovery so
important.

     Dr. Kinney emphasized that this unexpected result implies
that all radio galaxies might harbor quasars that are hidden from
view.

     The observations were made by Robert Antonucci and Todd Hurt of
the University of California at Santa Barbara, and Kinney.  Their
results appear in the September 22 issue of Nature.  

     Though Cygnus A is categorized as an elliptical galaxy, it
has an unusual peanut shape due to a dark band of dust encircling the
enigmatic nucleus.  The Hubble astronomers could only peek into the
core by taking advantage of a natural "periscope effect."  Dust
outside of the nucleus acts like a mirror to reflect the shorter
wavelengths, or blue component, of the light toward Earth.

     The astronomers used the ultraviolet sensitivity of the Faint
Object Spectrograph to look for the spectral signature of extremely
hot, supermassive stars hidden in the nucleus.  Such stars are
theorized as one possible explanation for Cygnus A's powerful optical
emissions.

     Instead, the resulting ultraviolet spectrum was so unusual
that astronomers puzzled over the data for three months before
reaching their startling conclusion.  After much analysis, they
realized it was in part composed of the typical spectrum of a quasar. 
Such a spectrum possesses broad emission lines that indicate that gas
in the nucleus is swirling at high speeds.  "One caveat is that the
broad emission line could possibly be many narrow emission lines
blended together," Kinney said.  "We will double check that
possibility with more observations."  HST's ultraviolet sensitivity 
allowed this spectrum to be distinguished more easily from the
galaxy's starlight.

     Kinney emphasized that it is probably more than coincidence
to find a quasar embedded in the nearest extremely powerful radio
galaxy to Earth.  These results suggest that quasars might be common
to radio galaxies and might explain their powerful radio emissions,
she added.

     Though this provides an unexpected opportunity for close-up
study of the mysterious "engine" behind a quasar, these results add
further mystery as to the true nature of the powerhouse. 

     Previous ground-based radio observations show that there is
an elongated object in Cygnus A's core.  This is inconsistent with
black hole models that predict a compact point source of radiation. 
Supermassive black holes are a leading candidate for explaining a
quasar's prodigious outpouring of energy.

     The astronomers plan to use the Hubble Space Telescope to
study the spectrum of other radio galaxies and look for fingerprints
of other quasars.

     The Hubble Space Telescope is a project of international
cooperation between NASA and the European Space Agency (ESA).

- end -

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