DENVER, Colo. -- A team of astronomers has discovered the faintest galaxy yet. Even better news is that its right in our cosmic background.
The new galaxy is named Andromeda IX and is a dim bulb in the cosmological scheme of things. It is nearly twice as faint as the previous record holder: Ursa Minor dwarf spheroidal galaxy.
Andromeda IX is situated near M31, the Andromeda galaxy, and is so diffuse that it appears 100 times dimmer than the night sky.(see image )
The finding was detailed today here at the 204th meeting of the American Astronomical Society (AAS).
Clumps of faint stars
Astronomers from the Sloan Digital Sky Survey (SDSS) discussed Andromeda IX, the lowest luminosity galaxy yet found. The SDSS involves more than 200 astronomers in 13 institutions around the globe. SDSS is making a map of a quarter of the entire sky, determining the position and brightness of hundreds of millions of celestial objects.
In the new SDSS observations, clumps of faints stars were being sought.
Andromeda IX was found as a "satellite" galaxy of M31 at a distance of 2 million light years, said Daniel Zucker of the Max-Planck-Institute for Astronomy in Heidelberg, Germany. "The problem is like finding a needle in a haystack," Zucker told reporters.
Andromeda IX is 100,000 times fainter than the Milky Way.
Remarkably unimpressive
Zucker characterized Andromeda IX as "remarkably unimpressive." But studying such features could lead to an understanding of the distribution and the amount of dark matter - matter that influences the evolution of the universe gravitationally, but is not seen directly in our present observations.
Given the SDSS ability to find quite faint objects, Zucker said more of the dim galaxies are likely to be found. "Im hopeful," he said.
The Sloan Digital Sky Survey (SDSS) is a joint project of The University of Chicago, Fermilab, the Institute for Advanced Study, the Japan Participation Group, The Johns Hopkins University, the Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, University of Pittsburgh, Princeton University, the United States Naval Observatory, and the University of Washington.
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