From: yee@trident.arc.nasa.gov (Peter E. Yee)
Subject: NASA spacecraft "sees" object 2 billion light years away [Release 92-169] (Forwarded)
Apparently-To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
Organization: NASA Ames Research Center, Moffett Field, CA
Date: Thu, 8 Oct 1992 21:39:15 GMT

Mike Braukus
Headquarters, Washington, D.C.               October 8, 1992
(Phone:  202/358-0872)

Dolores Beasley
Goddard Space Flight Center, Greenbelt, Md.
(Phone:  301/286-2806)

Dr. Bernhard Haisch
Center for Extreme Ultraviolet Astrophysics
University of California, Berkeley
(Phone:  510/643-5639)


RELEASE:  92-169

NASA SPACECRAFT "SEES" OBJECT 2 BILLION LIGHT YEARS AWAY


     A powerful, exotic object 2 billion light-years beyond the Milky Way 
galaxy has been observed by astronomers using a new NASA spacecraft 
designed to detect radiation in the little-explored extreme ultraviolet 
portion of the electromagnetic spectrum.

     "Twenty years ago no one would have believed you could see out of the 
solar system at EUV wavelengths.  But now -- for the first time -- we 
actually have obtained a EUV spectrum for an object beyond our galaxy," 
said Dr. Ed Weiler, Chief of NASA's Ultraviolet and Visible Astrophysics 
Branch.

     The radiation source was observed by the Extreme Ultraviolet Explorer 
(EUVE) Spacecraft, launched into Earth orbit on June 7 to search the 
spectrum between visible light and x-rays.

     Observation of the EUV spectrum both inside and out of the Milky Way 
galaxy is often blocked by gas and dust in interstellar space.  However, the 
distribution of the gas and dust is uneven which allows the EUVE 
telescopes to see distant sources of radiation. 

     According to the EUVE science team, the object is a tremendously 
energetic elliptical galaxy that radiates as much energy as a trillion suns.  
Some astrophysicists think such a galaxy, called a "BL Lac Object," may 
contain at its center a super-sized black hole with a mass of 100 million 
suns and may be a cousin to the even more mysterious quasars.  

     The science team is headed by Prof. Stuart Bowyer and Dr. Roger 
Malina at the University of California-Berkeley Center for Extreme 
Ultraviolet Astrophysics.  

     BL Lac Objects, like PKS 2155-304, vary dramatically in brightness in 
all other spectral regions.  Now scientists have discovered that it was rock 
steady in the EUV for a day and a half, according to Dr. Herman Marshall, 
EUVE astronomer. 

     "This result is extremely interesting, but we would like more 
observations to confirm this," said Goddard's Dr. Yoji Kondo, EUVE Project 
Scientist. 

     "But it might be that we have found the right window, as Dr. Marshall 
has indicated, to see the steady infall of material onto the giant black hole 
that the theorists think may be at the very center of  this object," said Dr. 
Kondo.

     The EUVE satellite is now 11 weeks into a survey of the entire sky.  It 
will provide astronomers with their first detailed maps in several EUV 
energy bands.  Radiation at these energies is emitted by multi-million 
degree coronae on stars, by giant eruptions on novae, by the hot surfaces 
of white dwarfs and by other exotic sources in the cosmos such as the BL 
Lac object.

Other Observations

     One of the new EUV sources detected by the satellite early in the 
mission was the corona of a star much like the sun, located about 16 light-
years away from Earth.  A white dwarf companion 7 arc-minutes away also 
appears in the EUV image. 

     On July 8-9, an outburst was observed from a cataclysmic variable, RE 
1938-461, a closely orbiting pair of stars in which gravitational forces pull 
matter from the outermost layers of one star onto the surface of the other, 
a white dwarf companion.  The hot compressed stellar material generates 
an explosive burst of EUV radiation as it falls into the deep gravitational 
field of the white dwarf. 

     Other explosive events are flares on stars.  These are unpredictable, 
giant versions of eruptions known to occur on a much smaller scale on the 
sun.  The EUVE caught two such events on the red dwarf stars AT Mic and 
AU Mic.

Spacecraft, Operations Performing Fine 

     All instruments are performing at or above expected levels, according to 
instrument Principal Investigator Roger Malina.  The EUVE Science 
Operations Center, based at CEA, operates around the clock, sending 
commands to point the instruments at selected astronomical sources and 
recording the findings of the satellite's four telescopes and three 
spectrometers. 

     A novel feature is that the staff includes more than two dozen 
undergraduate students who are getting a unique hands-on educational 
experience. 

     Researchers and engineers in Berkeley are pouring over the calibration 
and check-out data obtained during the first 6 weeks of the mission.  
These data serve a dual purpose.  They verify the instrument performance 
and at the same time, give astronomers valuable, new measurements to 
test their models.

     The EUVE Project is managed by the NASA Goddard Space Flight 
Center, Greenbelt, Md., for the Office of Space Science and Applications, 
Washington, D.C. 

                                      - end -


NOTE TO EDITORS:  Three photographs are available to news media to 
accompany this release by calling the NASA Headquarters Broadcast and 
Imaging Branch at 202/453-8375:
                                        Color                    B&W
  HR 6094                        92-HC-597           92-H-728

       EUV Spectrum of           (no color)              92-H-729
       AU Microscopii

      PKS 2155-304               92-HC-673            92-H-730

A videotape to accompany this release containing an interview with Dr. 
Stuart Bowyer and Local Bubble animation also is available at the 
Broadcast and Imaging Branch.
Newsgroups: sci.space.news