first conclusive detection of what appear to be the leftover building blocks of galaxy formation -- neutral hydrogen clouds -- swarming around the Andromeda Galaxy, the nearest large spiral galaxy to the Milky Way
This new image of the nearby Andromeda galaxy represents the first conclusive detection of what appear to be the leftover building blocks its formation. Clouds of neutral hydrogen swarm around the large, spiral galaxy.
The image, released yesterday, was made with the National Science Foundation's Robert C. Byrd Green Bank Telescope.
This discovery might help scientists understand the structure and evolution of the Milky Way and all spiral galaxies, astronomers said. It also could help explain why certain young stars in mature galaxies are surprisingly bereft of the heavy elements that their contemporaries contain.
"Giant galaxies, like Andromeda and our own Milky Way, are thought to form through repeated mergers with smaller galaxies and through the accretion of vast numbers of even lower mass 'clouds' -- dark objects that lack stars and even are too small to call galaxies," said David A. Thilker of the Johns Hopkins University in Baltimore, Maryland. "Theoretical studies predict that this process of galactic growth continues today, but astronomers have been unable to detect the expected low mass 'building blocks' falling into nearby galaxies, until now."
The new findings are detailed in the Astrophysical
Journal Letters. A detailed explanation of the findings is here.
Credit: NRAO/AUI/NSF, WSRT
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