Exceptionally deep view of strange galaxy (2/5/09)
A spectacular new image of an unusual spiral galaxy in the Coma Galaxy Cluster has been created from data taken by the Advanced Camera for Surveys on the NASA/ESA Hubble Space Telescope. It reveals fine details of the galaxy, NGC 4921, as well as an extraordinary rich background of more remote galaxies stretching back to the early Universe.
The Coma Galaxy Cluster, in the northern constellation of Coma Berenices, the hair of Queen Berenice, is one of the closest very rich collections of galaxies in the nearby Universe. The cluster, also known as Abell 1656, is about 320 million light-years from Earth and contains more than 1000 members. The brightest galaxies, including NGC 4921 shown here, were discovered back in the late 18th century by William Herschel.
The galaxies in rich clusters undergo many interactions and mergers that tend to gradually turn gas-rich spirals into elliptical systems without much active star formation. As a result there are far more ellipticals and fewer spirals in the Coma Cluster than are found in quieter corners of the Universe.
NGC 4921 is one of the rare spirals in Coma, and a rather unusual one — it is an example of an "anaemic spiral" where the normal vigorous star formation that creates a spiral galaxy’s familiar bright arms is much less intense. As a result there is just a delicate swirl of dust in a ring around the galaxy, accompanied by some bright young blue stars that are clearly separated out by Hubble’s sharp vision. Much of the pale spiral structure in the outer parts of the galaxy is unusually smooth and gives the whole galaxy the ghostly look of a vast translucent jellyfish.
NGC 4921 – click for 1280×1309 image
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A Galaxy for Science and ResearchNGC 134 is a barred spiral with its spiral arms loosely wrapped around a bright, bar-shaped central region. The red features lounging along its spiral arms are glowing clouds of hot gas in which stars are forming, so-called HII regions. The galaxy also shows prominent dark lanes of dust across the disc, obscuring part of the galaxys starlight.
NGC 134 – Click for 1280×1024 imageMore: here
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Starburst Galaxy NGC 1313 (5/24/10)
The starburst galaxy NGC 1313 is a stellar incubator delivering stars on a scale rarely seen in a single galaxy of its size. Now a striking new Gemini Observatory image reveals the multitudes of glowing gas clouds in this galaxy’s arms. These colorful clouds are the tell-tale sign of star-formation in this prolific star factory.
Because the clouds of gas in stellar nurseries emit light from ionized gas they shine brightly in very specific colors (or wavelengths) so narrow-band filters were used on the Gemini Multi-Object Spectrograph on the Gemini South telescope in Chile to capture the colorful galactic lightscape. The unprecedented detail and clarity of the image reveals myriad bubbles, shock fronts, star clusters, and sites where massive stars are being born.
NGC 1313 – click for 1000×747 imageMore: here
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A galaxy blooming with new stars (12/15/11)
The VLT Survey Telescope (VST) has captured the beauty of the nearby spiral galaxy NGC 253. The new portrait is probably the most detailed wide-field view of this object and its surroundings ever taken. It demonstrates that the VST, the newest telescope at ESOs Paranal Observatory, provides broad views of the sky while also offering impressive image sharpness.
NGC 253 gleams about eleven and a half million light-years away in the southern constellation of Sculptor. It is often just called the Sculptor Galaxy, although other descriptive names include the Silver Coin or Silver Dollar Galaxy. It is easy to get a good look at NGC 253 through binoculars as it is one of the brightest galaxies in the sky after the Milky Ways closest, big galactic neighbour, the Andromeda Galaxy.
Astronomers have noted the widespread active star formation in NGC 253 and labelled it a "starburst" galaxy. The many bright clumps dotting the galaxy are stellar nurseries where hot young stars have just ignited. The radiation streaming from these giant blue-white babies makes the surrounding hydrogen gas clouds glow brightly (green in this image).
NGC 253 – click for 1280×1012 imageMore: here
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