NASA Headquarters, Washington, DC
Goddard Space Flight Center, Greenbelt, MD
Space Telescope Science Institute, Baltimore, MD

October 8, 1998


Stretching the vision of NASA's Hubble Space Telescope farther across space and further back into time than ever before, astronomers have peered into a previously unseen realm of the universe.

A "long exposure" infrared image taken with Hubble’s Near Infrared Camera and Multi-Object Spectrometer (NICMOS) has uncovered the faintest galaxies ever seen.

Astronomers believe some of these galaxies could be over 12 billion light-years away (depending on cosmological models) – making them the farthest objects ever seen. A powerful new generation of telescopes will be needed to confirm the suspected distances.

"NICMOS has parted the dark curtain that previously blocked our view of very distant objects and revealed a whole new cast of characters. We now have to study them to find out who, what and where they are. We are still finding new frontiers," says Rodger I. Thompson of the University of Arizona in Tucson.

"This is just our first tentative glimpse into the very remote universe," says Alan Dressler of the Carnegie Observatories in Pasadena, CA. "What we see may be the first stages of galaxy formation. But the objects are so faint that their true nature can only be explored with the advanced telescopes of the future."

"This observation is a major step toward fulfilling one of Hubble's key objectives: to search for the faintest and farthest objects in the universe," adds Ed Weiler, NASA's acting Associate Administrator for Space Science.

In a separate discovery, Thompson also found that faint red galaxies matched up with compact blue knots of light seen in the earlier visible light image. "This means that some objects that appeared to be separate galaxies in the optical image are really hot star-forming regions in much larger older galaxies," he says.

Prior to the NICMOS observation, a ten-day long exposure called the Hubble Deep Field was Space Telescope's benchmark for the "deepest" view into the universe (with the exception of the cosmic microwave background that is farther away than any structures seen in the universe).

Astronomers had to wait for the infrared camera to be installed on Hubble to look for unseen galaxies beyond the limits of the visible deep field photograph. Infrared sensitivity was needed because the expansion of the universe is expected to stretch the light of distant galaxies down to infrared wavelengths.

Thompson selected a portion of the original Hubble deep field and took long exposures with the Hubble's near infrared camera. When the infrared and visible-light pictures were compared, Thompson found many new objects that were not seen in visible light.

In results to be published in the Astronomical Journal, Thompson precisely measured the infrared "colors" of the objects. He found some objects that had the expected color of a galaxy too distant to be detected in the optical HDF.

Scheduled for launch in the year 2007, the Next Generation Space Telescope (NGST) will be used to take infrared spectra of candidate galaxies to confirm their distances, and its higher resolution will help reveal the shapes of these early objects.

The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) for NASA, under contract with the Goddard Space Flight Center, Greenbelt, MD. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA).

Images and photo captions associated with this release are available on the Internet at:

Images and photo captions associated with this release are available on the Internet.



A NASA Hubble Space Telescope view of the faintest galaxies ever seen in the universe, taken in infrared light with the Near Infrared Camera and Multi-Object Spectrometer (NICMOS).

The picture contains over 300 galaxies having spiral, elliptical and irregular shapes. Though most of these galaxies were first seen in 1995 when Hubble was used to take a visible-light deep exposure of the same field, NICMOS uncovers many new objects. Most of these objects are too small and faint to be apparent in the full field NICMOS view.

Some of the reddest and faintest of the newly detected objects may be over 12 billion light-years away, as derived from a standard model of the universe. However, a powerful new generation of telescopes will be needed to confirm the suspected distances of these objects.

The field of view is 2 million light-years across, at its maximum. Yet, on a cosmic scale, it represents only a thin pencil beam look across the universe. The area of sky is merely 1/100th the apparent diameter on the full moon.

Two close-up NICMOS views of candidate objects which may be over 12 billion light-years away. Each candidate is centered in the frame. The reddish color may mean all of the starlight has been stretched to infrared wavelengths by the universe's expansion. Alternative explanations are that the objects are closer to us, but the light has been reddened by dust scattering. A new generation of telescopes will be needed to make follow-up observations capable of establishing true distance.

The image was taken in January 1998 and required an exposure time of 36 hours to detect objects down to 30th magnitude. Hubble was aimed in the direction of the constellation Ursa Major, in a region just above the handle of the Big Dipper. The color corresponds to blue (0.45 microns), green (1.1 microns) and red (1.6 microns).

Credit: Rodger I. Thompson (University of Arizona), and NASA


A galaxy can look quite different in visible vs infrared light. This is a comparison view of a spiral galaxy in the Hubble Deep Field -- Hubble Space Telescope's view of the faintest galaxies ever seen in the universe.

The galaxy is disk-shaped like our Milky Way and tilted obliquely along our line of sight. It is located in the constellation Ursa Major. The smaller clumps in the picture are likely other galaxies.

In the visible-light picture, taken with the Wide Field and Planetary Camera 2 (WFPC2) in 1995, the galaxy looks uncharacteristically lumpy. That's because only the bright blue knots of starbirth are detected by the WFPC2.

The underlying disk structure, containing older stars, is seen clearly in this infrared Deep Field image taken with Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) in January 1998.

These types of comparative observations will help astronomers better understand the evolution of galaxies.

Credit: Rodger I. Thompson (University of Arizona), and NASA

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