Mike Braukus Headquarters, Washington, D.C. October 8, 1992 (Phone: 202/358-0872) EMBARGOED UNTIL 1 P.M. EDT 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. - more - - 2 - 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. - more - - 3 - 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.