Dark galaxy
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A dark galaxy is a galaxy-sized object containing very few or no stars (hence 'dark'). Held together by dark matter, it may also contain gas and dust. No dark galaxy with a black hole as a center has yet been discovered.
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[edit] Candidates
[edit] HE0450-2958
HE0450-2958 is an unusual quasar as no host galaxy was detected around it.[1] It has been suggested that this may be a dark galaxy in which a quasar has become active. However subsequent observations revealed that a normal host galaxy is probably present.[2]
[edit] VIRGOHI21
The discovery of VIRGOHI21 was announced in February 2005, and it was the first good candidate for a true dark galaxy. It was found by looking for the 21cm-wavelength radio waves emitted by hydrogen (HI). Its dynamics are apparently inconsistent with the predictions of the MOND theory (Funkhouser 2005).
[edit] See also
[edit] References
- ^ Magain, P. et al. (2005), of a bright quasar without a massive host galaxy, Nature, 437, 381
- ^ Merritt, D. et al. (2005), nature of the HE0450-2958 System, arXiv:astro-ph/0511315
- Britt, Roy (2005-02-23). "First Invisible Galaxy Discovered in Cosmology Breakthrough". Space.com. http://www.space.com/scienceastronomy/050223_dark_galaxy.html.
- Battersby, Stephen (2003-10-20). "Astronomers find first 'dark galaxy'". New Scientist. http://www.newscientist.com/article.ns?id=dn4272.
- Clark, Stuart (2005-02-23). "Astronomers claim first 'dark galaxy' find". NewScientist.com news service. http://www.newscientist.com/article.ns?id=dn7056. Retrieved 2006-10-26.
- Funkhouser, Scott (2005). "Testing MOND with VirgoHI21". Monthly Notices of the Royal Astronomical Society 364: 237. doi:. http://arxiv.org/abs/astro-ph/0503104. Retrieved 2006-10-26.
- Shiga, David (2005-02-26). "Ghostly Galaxy: Massive, dark cloud intrigues scientists". Science News Online 167 (9): 131. doi:. http://www.sciencenews.org/view/generic/id/5929/title/Ghostly_Galaxy_Massive%2C_dark_cloud_intrigues_scientists. Retrieved 2008-09-14.
[edit] External links
- Universe Today, Some Galaxies Are Made Almost Entirely of Dark Matter
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