Editing Elliptical galaxy (section)

==Star formation==
In recent years, evidence has shown that a reasonable proportion (~25%) of early-type (E, ES and S0) galaxies have residual gas reservoirs<ref name="Young2011">{{cite journal|author=Young, L. M.|display-authors=etal|date=June 2011|title=The Atlas3D project – IV: the molecular gas content of early-type galaxies|journal=Monthly Notices of the Royal Astronomical Society|volume=414|issue=2|pages=940–967|arxiv=1102.4633|bibcode=2011MNRAS.414..940Y|doi=10.1111/j.1365-2966.2011.18561.x|doi-access=free |s2cid=119267988}}</ref>
and low-level star formation.<ref name="Crocker2011">{{cite journal|last=Crocker|first=A. F.|display-authors=etal|date=January 2011|title=Molecular gas and star formation in early-type galaxies|journal=Monthly Notices of the Royal Astronomical Society|volume=410|issue=2|pages=1197–1222|arxiv=1007.4147|bibcode=2011MNRAS.410.1197C|doi=10.1111/j.1365-2966.2010.17537.x|doi-access=free |s2cid=54764264}}</ref>

[[Herschel Space Observatory]] researchers have speculated that the central black holes in elliptical galaxies keep the gas from cooling enough for star formation.<ref>{{Cite web|url=http://www.hngn.com/articles/25442/20140227/red-and-dead-galaxies-have-beating-black-hole-hearts-preventing-star-formation.htm|title=Red And Dead Galaxies Have Beating Black Hole 'Hearts', Preventing Star Formation &#124; HNGN - Headlines & Global News|date=27 February 2014 |accessdate=8 May 2023}}</ref>