Faint blue galaxy

The faint blue galaxy (F.B.G.) problem in astrophysics first arose with observations starting in 1978 that there were more galaxies with a bolometric magnitude > 22 than then-current theory predicted.[1][2][3] Galaxies can appear faint because they are small or because they are far away. Neither explanation, nor any combination, initially matched the observations. The distribution of these galaxies has since been found to be consistent with Cosmic inflation, measurements of the Cosmic Microwave Background, and a nonzero cosmological constant, that is, with the existence of the now-accepted dark energy.[4][5] It thus serves as a confirmation of supernova observations requiring dark energy.

A second problem arose in 1988, with even deeper observations showing a much greater excess of faint galaxies.[6] These are now interpreted as dwarf galaxies experiencing large bursts of stellar formation, resulting in blue light from young, massive stars.[7] Thus F.B.G.s are extremely bright for their size and distance.

Most F.B.G.s appear between red-shift 0.5 and 2. It is believed that they disappear as separate objects by merger with other galaxies.[8][9]


  1. ^ Kron R 1978 Ph.D. Thesis, University of California, Berkeley
  2. ^ Peterson, B.A.; Ellis, R.S.; Kibblewhite, E.J.; Bridgeland, M.T.; Hooley, T.; Horne, D. (Nov 1, 1979), "Number magnitude counts of faint galaxies", Astrophysical Journal Letters, 233: L109–L113, Bibcode:1979ApJ...233L.109P, doi:10.1086/183087
  3. ^ Tyson, J.A.; Jarvis, J.F. (June 15, 1979), "Evolution of galaxies - Automated faint object counts to 24th magnitude", Astrophysical Journal Letters, 230: L153–L156, Bibcode:1979ApJ...230L.153T, doi:10.1086/182982
  4. ^ Yoshii, Yuzuru; Takahara, Fumio (Nov 1, 1989), "On the redshift-volume measurement of the cosmological density parameter", Astrophysical Journal, 346: 28–33, Bibcode:1989ApJ...346...28Y, doi:10.1086/167983
  5. ^ David C., Koo (June 21–23, 1989). "The evolution of field galaxies - Is Omega = 1?". Evolution of the universe of galaxies; Proceedings of the Edwin Hubble Centennial Symposium. Berkeley, CA: Astronomical Society of the Pacific. pp. 268–285. Bibcode:1990ASPC...10..268K.
  6. ^ Broadhurst, T.J.; Ellis, R.S.; Shanks, T. (Dec 1, 1988), "The Durham/Anglo-Australian Telescope faint galaxy redshift survey", Monthly Notices of the Royal Astronomical Society, 235 (3): 827–856, Bibcode:1988MNRAS.235..827B, doi:10.1093/mnras/235.3.827
  7. ^ Colless, Matthew; Ellis, Richard S.; Broadhurst, T.J.; Taylor, Keith; Peterson, Bruce A. (March 1993), "Faint blue galaxies - High or low redshift?", Monthly Notices of the Royal Astronomical Society, 261: 19–38, Bibcode:1993MNRAS.261...19C, doi:10.1093/mnras/261.1.19
  8. ^ Carlberg, R.G. (November 1992), "Merging and fast galaxy evolution", Astrophysical Journal Letters, 399 (1): L31–L34, Bibcode:1992ApJ...399L..31C, doi:10.1086/186599
  9. ^ Carlberg, R.G.; Charlot, Stephane (September 1992), "Faint galaxy evolution via interactions", Astrophysical Journal, 397 (1): 5–13, Bibcode:1992ApJ...397....5C, doi:10.1086/171759
Coma Filament

Coma Filament is a galaxy filament. The filament contains the Coma Supercluster of galaxies and forms a part of the CfA2 Great Wall.

Lynx–Ursa Major Filament

Lynx–Ursa Major Filament (LUM Filament) is a galaxy filament.The filament is connected to and separate from the Lynx–Ursa Major Supercluster.

Perseus–Pegasus Filament

Perseus–Pegasus Filament is a galaxy filament containing the Perseus-Pisces Supercluster and stretching for roughly a billion light years (or over 300/h Mpc). Currently, it is considered to be one of the largest known structures in the universe. This filament is adjacent to the Pisces–Cetus Supercluster Complex.

Radio Galaxy Zoo

Radio Galaxy Zoo (RGZ) is an internet crowdsourced citizen science project that seeks to locate supermassive black holes in distant galaxies. It is hosted by the web portal Zooniverse. The scientific team want to identify black hole/jet pairs and associate them with the host galaxies. Using a large number of classifications provided by citizen scientists they hope to build a more complete picture of black holes at various stages and their origin. It was initiated in 2010 by Ray Norris in collaboration with the Zooniverse team, and was driven by the need to cross-identify the millions of extragalactic radio sources that will be discovered by the forthcoming Evolutionary Map of the Universe survey. RGZ is now led by scientists Julie Banfield and Ivy Wong. RGZ started operations on 17 December 2013.

Ursa Major Filament

Ursa Major Filament is a galaxy filament. The filament is connected to the CfA Homunculus, a portion of the filament forms a portion of the "leg" of the Homunculus.

Active nuclei
Energetic galaxies
Low activity
See also

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.