Abell 2218: Difference between revisions
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dubious most distant galaxy - later claims by other galaxies at lower redshifts have better data, IOK-1 is commonly accepted, at a lower redshift and later discovery |
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'''Abell 2218''' is a [[Galaxy cluster|cluster of galaxies]] about [[10 zettametres|2 billion]] [[light-year]]s away in the [[constellation]] [[Draco (constellation)|Draco]]. Acting as a powerful [[Gravitational lens|lens]], it magnifies and distorts all galaxies lying behind the cluster core into long [[Arc (geometry)|arcs]]. The lensed galaxies are all stretched along the cluster's center and some of them are multiply imaged. Those multiple images usually appear as a pair of images with a third — generally fainter — counter image, as is the case for the very distant object. |
'''Abell 2218''' is a [[Galaxy cluster|cluster of galaxies]] about [[10 zettametres|2 billion]] [[light-year]]s away in the [[constellation]] [[Draco (constellation)|Draco]]. Acting as a powerful [[Gravitational lens|lens]], it magnifies and distorts all galaxies lying behind the cluster core into long [[Arc (geometry)|arcs]]. The lensed galaxies are all stretched along the cluster's center and some of them are multiply imaged. Those multiple images usually appear as a pair of images with a third — generally fainter — counter image, as is the case for the very distant object. |
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Abell 2218 was used as a gravitational lens to discover the most distant known object in the universe as of 2004. The object, a galaxy some 13 billion years old, is seen from Earth as it would have been just 750 million years after the [[Big Bang]].<ref>[http://www.msnbc.msn.com/id/4274187/ MSNBC: "Galaxy ranks as most distant object in cosmos"]</ref> |
Abell 2218 was used as a gravitational lens to discover the most distant known object in the universe as of 2004. The object, a galaxy some 13 billion years old, is seen from Earth as it would have been just 750 million years after the [[Big Bang]].<ref>[http://www.msnbc.msn.com/id/4274187/ MSNBC: "Galaxy ranks as most distant object in cosmos"]</ref>{{dubious}} |
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The [[color]] of the lensed galaxies is a function of their distances and types. The [[Orange (colour)|orange]] arc is an [[elliptical galaxy]] at moderate redshift (z=0.7). The [[blue]] arcs are star-forming galaxies at intermediate redshift (z=1-2.5). The encircled very red pair is the newly discovered star-forming galaxy at about redshift 7. |
The [[color]] of the lensed galaxies is a function of their distances and types. The [[Orange (colour)|orange]] arc is an [[elliptical galaxy]] at moderate redshift (z=0.7). The [[blue]] arcs are star-forming galaxies at intermediate redshift (z=1-2.5). The encircled very red pair is the newly discovered star-forming galaxy at about redshift 7.{{cn}} |
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The lensed galaxies are particularly numerous, as we are looking in between two mass clumps, in a saddle region where the magnification is quite large. |
The lensed galaxies are particularly numerous, as we are looking in between two mass clumps, in a saddle region where the magnification is quite large. |
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==References== |
==References== |
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<div class="references-small"><references/></div> |
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{{Sky|16|35|54|+|66|13|00|2000000000}} |
{{Sky|16|35|54|+|66|13|00|2000000000}} |
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[[Category:Draco constellation]] |
[[Category:Draco constellation]] |
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Revision as of 05:04, 22 October 2010
| Abell 2218 | |
|---|---|
 | |
| Observation data (Epoch J2000) | |
| Constellation(s) | Draco |
| Right ascension | 16h 35m 54s[1] |
| Declination | +66° 13′ 00″[1] |
| Number of galaxies | ~10,000 |
Abell 2218 is a cluster of galaxies about 2 billion light-years away in the constellation Draco. Acting as a powerful lens, it magnifies and distorts all galaxies lying behind the cluster core into long arcs. The lensed galaxies are all stretched along the cluster's center and some of them are multiply imaged. Those multiple images usually appear as a pair of images with a third — generally fainter — counter image, as is the case for the very distant object.
Abell 2218 was used as a gravitational lens to discover the most distant known object in the universe as of 2004. The object, a galaxy some 13 billion years old, is seen from Earth as it would have been just 750 million years after the Big Bang.[2][dubious – discuss]
The color of the lensed galaxies is a function of their distances and types. The orange arc is an elliptical galaxy at moderate redshift (z=0.7). The blue arcs are star-forming galaxies at intermediate redshift (z=1-2.5). The encircled very red pair is the newly discovered star-forming galaxy at about redshift 7.[citation needed]
The lensed galaxies are particularly numerous, as we are looking in between two mass clumps, in a saddle region where the magnification is quite large.
See also
External links
- Release about Abell 2218 at ESA/Hubble
- Astronomy Picture of the Day - Abell 2218: A Galaxy Cluster Lens - 2010 June 20
References
- ^ a b "NASA/IPAC Extragalactic Database". Results for Abell 2218. Retrieved 2006-09-18.
- ^ MSNBC: "Galaxy ranks as most distant object in cosmos"
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