Polar-ring galaxy: Difference between revisions
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[[Image:NGC 4650A I HST2002.jpg|right|thumb|140px|[[NGC 4650A]] is one example of a polar-ring galaxy]] | [[Image:NGC 4650A I HST2002.jpg|right|thumb|140px|[[NGC 4650A]] is one example of a polar-ring galaxy]] | ||
== | A '''polar-ring galaxy''' is a type of [[galaxy]] in which an outer ring of gas and stars rotates over the poles of the galaxy.<ref name="binneymerrifield1998"/>{{cite book | ||
| author=James Binney, Michael Merrifield | |||
| year=[[1998]] | |||
| title=Galactic Astronomy | |||
| publisher=Princeton University Press | |||
| location=Princeton, New Jersey | |||
| id=ISBN 0-691-00402-1}} Polar rings may be found around 0.5% of all nearby [[lenticular galaxies]], and it is possible that 5% of lenticular galaxies may have had polar rings at some point during their lifetimes.<ref name="whitmoreetal1990">{{cite journal | |||
| author= B. C. Whitmore, R. A. Lucas, D. B. McElroy, T. Y. Steiman-Cameron, P. D. Sackett, R. P. Olling | |||
| title=New observations and a photographic atlas of polar-ring galaxies | |||
| journal=Astronomical Journal | |||
| year=1990 | |||
| volume=100 | |||
| pages=1489-1522, 1721-1755 | |||
| url=http://adsabs.harvard.edu/abs/1990AJ....100.1489W}}</ref> The best known polar-ring galaxy is [[NGC 4650A]]. It is theorized that these galaxies are formed by the collision of two separate galaxies. The collision results in a structure composed of two rings of material rotating at an approximate right angle to each other. | |||
The first four galaxies that were identified as polar-ring galaxies were [[NGC 2685]],<ref name="schectergunn1978">{{cite journal | |||
| author=P. L. Schecter, J. E. Gunn | |||
== | | title=NGC 2685 - Spindle or pancake | ||
| journal=Astronomical Journal | |||
| year=1978 | |||
|- | | volume=83 | ||
| pages=1360-1362 | |||
| | | url=http://adsabs.harvard.edu/abs/1978AJ.....83.1360S}}</ref> [[NGC 4650A]],<ref name="sersic1967">{{cite journal | ||
| author=J. L. Sérsic | |||
| [[A 0136-0801]], | | title=Southern Peculiar Galaxies III | ||
|- | | journal=Zeitschrift für Astrophysik | ||
| year=1967 | |||
| | | volume=67 | ||
| pages=306-311 | |||
| url=http://adsabs.harvard.edu/abs/1967ZA.....67..306S}}</ref><ref name="whitmoreetal1987">{{cite journal | |||
| author=B. C. Whitmore, D. B. McElroy, F. Schweizer | |||
| title=The shape of the dark halo in polar-ring galaxies | |||
| journal=Astrophysical Journal | |||
| year=1987 | |||
| volume=314 | |||
| pages=439-456 | |||
| url=http://adsabs.harvard.edu/abs/1987ApJ...314..439W}}</ref> [[A 0136 -0801]],<ref name="schweizeretal1983">{{cite journal | |||
| author=F. Schweizer, B. C. Whitmore, V. C. Rubin | |||
| title=Colliding and merging galaxies. II - S0 galaxies with polar rings | |||
| journal=Astronomical Journal | |||
| year=1983 | |||
| volume=88 | |||
| pages=909-925 | |||
| url=http://adsabs.harvard.edu/abs/1983AJ.....88..909S}}</ref> and [[ESO 415 -G26]].<ref name=""whitmoreetal1987" /> While these galaxies have been extensively studied, many other polar-ring galaxies have since been identified.<ref name="whitmoreetal1990"> | |||
==References== | ==References== | ||
<div class="references-small"><references/></div> | |||
==External links== | ==External links== | ||
* [http://antwrp.gsfc.nasa.gov/apod/ap990510.html An image of NGC 4650A, a Polar Ring Galaxy] | * [http://antwrp.gsfc.nasa.gov/apod/ap990510.html An image of NGC 4650A, a Polar Ring Galaxy] | ||
* [http://hubblesite.org/newscenter/archive/releases/1999/16/ Hubblesite.org] Retrieved [[January 2007]] | |||
[[Category:Galaxy morphological types]] | [[Category:Galaxy morphological types]] | ||
[[de:Polarring-Galaxie]] | [[de:Polarring-Galaxie]] | ||
Revision as of 09:21, 11 May 2007
A polar-ring galaxy is a type of galaxy in which an outer ring of gas and stars rotates over the poles of the galaxy.[1]James Binney, Michael Merrifield (1998). Galactic Astronomy. Princeton, New Jersey: Princeton University Press. ISBN 0-691-00402-1. Polar rings may be found around 0.5% of all nearby lenticular galaxies, and it is possible that 5% of lenticular galaxies may have had polar rings at some point during their lifetimes.[2] The best known polar-ring galaxy is NGC 4650A. It is theorized that these galaxies are formed by the collision of two separate galaxies. The collision results in a structure composed of two rings of material rotating at an approximate right angle to each other.
The first four galaxies that were identified as polar-ring galaxies were NGC 2685,[3] NGC 4650A,[4][5] A 0136 -0801,[6] and ESO 415 -G26.Cite error: The opening <ref> tag is malformed or has a bad name While these galaxies have been extensively studied, many other polar-ring galaxies have since been identified.<ref name="whitmoreetal1990">
References
- ↑ Cite error: Invalid
<ref>tag; no text was provided for refs namedbinneymerrifield1998 - ↑ B. C. Whitmore, R. A. Lucas, D. B. McElroy, T. Y. Steiman-Cameron, P. D. Sackett, R. P. Olling (1990). "New observations and a photographic atlas of polar-ring galaxies". Astronomical Journal 100: 1489-1522, 1721-1755. http://adsabs.harvard.edu/abs/1990AJ....100.1489W.
- ↑ P. L. Schecter, J. E. Gunn (1978). "NGC 2685 - Spindle or pancake". Astronomical Journal 83: 1360-1362. http://adsabs.harvard.edu/abs/1978AJ.....83.1360S.
- ↑ J. L. Sérsic (1967). "Southern Peculiar Galaxies III". Zeitschrift für Astrophysik 67: 306-311. http://adsabs.harvard.edu/abs/1967ZA.....67..306S.
- ↑ B. C. Whitmore, D. B. McElroy, F. Schweizer (1987). "The shape of the dark halo in polar-ring galaxies". Astrophysical Journal 314: 439-456. http://adsabs.harvard.edu/abs/1987ApJ...314..439W.
- ↑ F. Schweizer, B. C. Whitmore, V. C. Rubin (1983). "Colliding and merging galaxies. II - S0 galaxies with polar rings". Astronomical Journal 88: 909-925. http://adsabs.harvard.edu/abs/1983AJ.....88..909S.