Penn State Graduate Student Featured Today at NASA Televised Press Conference

13 March 2001 -- A graduate student and member of a Penn State team of astronomers, Ann Hornschemeier, will announce at a televised NASA press conference today that the team has used NASA's Chandra X-ray Telescope to made a historic 1-million-second observation of X-rays coming from of an area of the sky near the Big Dipper.

This area of sky is now the most intensively surveyed by two of NASA's Great Observatories: the Hubble Space Telescope, which detects visible light, and the Chandra X-ray Observatory, which detects X-rays.

The team has revealed new information about the X-ray glow that pervades the sky. Previously X-rays from only massive black holes-the brightest and loudest contributors-could be observed, but the team now has revealed small and very distant black holes only a few times the mass of our Sun, whose

dim X-ray emissions are the equivalent of only a whisper.

The Chandra observations were made using the Advanced CCD Imaging Spectrometer (ACIS), conceived and developed for NASA by Penn State and

Massachusetts Institute of Technology under the leadership of Penn State professor Gordon Garmire. The ACIS detector is a sophisticated version of the CCD detectors commonly used in digital cameras or video cameras.

Hornschemeier's work is supported, in part, by a NASA Graduate Student Researcher Program (GRSP) fellowship.

RESEARCH CONTACTS:

Ann Hornschemeier -- 814-863-0182 ahornschemeier@astro.psu.edu

Gordon Garmire -- 814-865-1117 ggarmire@astro.psu.edu

Niel Brandt   -- 814-865-3509  nbrandt@astro.psu.edu

Donald Schneider   -- 814-863-9554  dschneider@astro.psu.edu

PUBLIC INFORMATION CONTACT:

Barbara Kennedy -- 814-863-4682 science@psu.edu

Supermassive black holes lurking in the centers of galaxies are the noisy monsters of the universe. They send out loud "screams" of energy, including powerful X-rays, as they greedily gobble up all the material within the far-reaching grasp of their massive gravity. While astronomers using X-ray telescopes have been able to find supermassive black holes because they have such loud X-ray signals, they have not been able to detect smaller black holes at distances much farther away than our local neighborhood of galaxies because their quieter X-ray signatures were hidden by all the noise. Now, a Penn State team of astronomers has been able to detect the X-ray whispers of very small black holes--some almost as small as our Sun in normal spiral galaxies, some of them incredibly distant from Earth and several billion years younger than the Milky Way.

"We are finding that we can now use X-rays to study spiral galaxies like the one we call home," says Ann Hornschemeier, a Penn State graduate student and member of the Penn State team lead by Gordon Garmire, the Evan Pugh professor of astronomy and astrophysics. She recently presented the group's findings at a televised press conference at NASA headquarters in Washington, DC. Her advisor, Niel Brandt, professor of astronomy and astrophysics, is leading the analysis of the Garmire team's data. Her brother, Paul Hornschemeier, drew this cartoon to help explain the team's research.

In addition to Garmire, Brandt, and Hornschemeier, other members of the Penn State team include Donald Schneider, Amy Barger, P. S. Broos, L. L. Cowie, Leisa Townsley, Mark Bautz, David Burrows, George Chartas, Eric Feigelson, R. E. Griffiths, D. Lumb, John Nousek, Lawrence Ramsey, and W. L. W. Sargent.

NASA News Release

13 March 2001

Dolores Beasley

Headquarters, Washington, DC

(Phone: 202/358-1753)

Steve Roy

Marshall Space Flight Center, Huntsville, AL

(Phone: 256/544-6535)

Megan Watzke

Harvard-Smithsonian Center for Astrophysics, Cambridge, MA

(Phone: 617/496-7998)

RELEASE: 01-37

DEEPEST X-RAYS EVER REVEAL UNIVERSE TEEMING WITH BLACK HOLES

For the first time, astronomers believe they have proof black holes of all sizes once ruled the universe. NASA's Chandra X-ray Observatory provided the deepest X-ray images ever recorded, and those pictures deliver a novel look at the past 12 billion years of black holes.

Two independent teams of astronomers today presented images that contain the faintest X-ray sources ever detected, which include an abundance of active super-massive black holes.

"The Chandra data show us that giant black holes were much more active in the past than at present," said Riccardo Giacconi, of Johns Hopkins University and Associated Universities, Inc., Washington, DC. The exposure is known as "Chandra Deep Field South" since it is located in the Southern Hemisphere constellation of Fornax. "In this million-second image, we also detect relatively faint X-ray emission from galaxies, groups, and clusters of galaxies."

The images, known as Chandra Deep Fields, were obtained during many long exposures over the course of more than a year. Data from the Chandra Deep Field South will be placed in a public archive for scientists beginning today.

"For the first time, we are able to use X-rays to look back to a time when normal galaxies were several billion years younger," said Ann Hornschemeier, Pennsylvania State University, University Park. The group's

500,000-second exposure included the Hubble Deep Field North, allowing scientists the opportunity to combine the power of Chandra and the Hubble Space Telescope, two of NASA's Great Observatories. The Penn State team recently acquired an additional 500,000 seconds of data, creating another one-million-second Chandra Deep Field, located in the constellation of Ursa Major.

The images are called Chandra Deep Fields because they are comparable to the famous Hubble Deep Field in being able to see further and fainter objects than any image of the universe taken at X-ray wavelengths. Both Chandra Deep Fields are comparable in observation time to the Hubble Deep Fields, but cover a much larger area of the sky.

"In essence, it is like seeing galaxies similar to our own Milky Way at much earlier times in their lives," Hornschemeier added. "These data will help scientists better understand star formation and how stellar-sized

black holes evolve." Combining infrared and X-ray observations, the Penn State team also found veils of dust and gas are common around young black holes.

Another discovery to emerge from the Chandra Deep Field South is the detection of an extremely distant X-ray quasar, shrouded in gas and dust. "The discovery of this object, some 12 billion light years away, is key to understanding how dense clouds of gas form galaxies, with massive black holes at their centers," said Colin Norman of Johns Hopkins University.

The Chandra Deep Field South results were complemented by the extensive use of deep optical observations supplied by the European Southern Observatory in Garching, Germany. The Penn State team obtained optical spectroscopy and imaging using the Hobby-Eberly Telescope in Ft. Davis, TX, and the Keck Observatory atop Mauna Kea, HI.

Chandra's Advanced CCD Imaging Spectrometer was developed for NASA by Penn State and Massachusetts Institute of Technology under the leadership of Penn State Professor Gordon Garmire. NASA's Marshall Space Flight Center, Huntsville, AL, manages the Chandra program for the Office of Space Science, Washington, DC. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA.

More information is available on the Internet at:

http://chandra.harvard.edu

http://chandra.nasa.gov