A void galaxy is a galaxy located in a cosmological void.[1] Few galaxies exist in voids; most are located in sheets, walls and filaments that surround voids and supervoids.[2][3] Many void galaxies are connected through void filaments[4] or tendrils,[5] less massive versions of the regular galaxy filaments that surround voids. These filaments are often straighter than their non-void counterparts due to the lack of influence by surrounding filaments.[4] These filaments can even be rich enough to form poor galaxy clusters.[6] The void galaxies themselves are thought to represent pristine examples of galactic evolution, having few neighbours, and likely to have formed from pure intergalactic gas.[7]
Formation
It is theorised by many astrophysicists that void galaxies are the result of large galactic filaments being pulled by the gravity of a major super cluster out of the less densely populated areas, causing voids such as the Boötes Void to grow. Galaxies such as MCG+01-02-015 are sometimes left behind from such events.[8]
^Rien van de Weygaert; Platen, Erwin; Tigrak, Esra; Hidding, Johan; Thijs van der Hulst; Aragon-Calvo, Miguel A.; Stanonik, Kathryn; Jacqueline van Gorkom (17 December 2009). "The Cosmically Depressed: Life, Sociology and Identity of Voids". Galaxies in Isolation: Exploring Nature Versus Nurture. 421: 99. arXiv:0912.3473v1. Bibcode:2010ASPC..421...99V.
^Kuhn, B.; Hopp, U.; Elsaesser, H. (February 1997). "Results of a search for faint galaxies in voids". Astronomy and Astrophysics. 318: 405–415. Bibcode:1997A&A...318..405K. ISSN0004-6361.
^ abcdefghiKim, Chulhee; Boller, Th.; Ghosh, Kajal K.; Swartz, Douglas A.; Ramsey, Brian D. (January 2001). "Detection of X-Ray Emission from Galaxies inside the Bootes Void". The Astrophysical Journal. 546 (2): L91–L95. Bibcode:2001ApJ...546L..91K. doi:10.1086/318868.
^ abcdefCruzen, Shawn; Wehr, Tara; Weistrop, Donna; Angione, Ronald J.; Hoopes, Charles (January 2002). "Spectroscopy of Galaxies in the Bootes Void". The Astronomical Journal. 123 (1): 142–158. Bibcode:2002AJ....123..142C. doi:10.1086/324739.
^Tully, Brent. "The Local Void"(PDF). AMIGA - Analysis of the interstellar Medium of Isolated Galaxies. Archived from the original(PDF) on 15 December 2009.