The effect of Helium-enhanced stellar populations on the ultraviolet upturn phenomenon of early-type galaxies. (5th March 2015)

• Record Type: Journal Article
• Authors: Chung, Chul; Yoon, Suk-Jin; Lee, Young-Wook
• Editors: Montmerle, Thierry
• Is Part Of: Proceedings of the International Astronomical Union. Volume 10:Number H16(2012)Highlights
• Page Start: 121
• Page End: 121
• Publication Date: 2015-03-05
• Subjects: galaxies: elliptical and lenticular, -- CD, -- galaxies: evolution, -- galaxies: stellar content, -- ultraviolet: galaxies; Astronomy -- Congresses; Astronomy -- Periodicals; 520
• DOI: 10.1017/S1743921314004839
• Languages: English
• ISSNs: 1743-9213

Abstract

Abstract: We present new population synthesis models (Chung et al. 2011 ) for quiescent early-type galaxies (ETGs) with UV-upturn phenomenon using relatively metal-poor and helium-enhanced subpopulations in the model. We find that the presence of helium-enhanced subpopulations in ETGs can naturally reproduce the strong UV-upturns observed in giant elliptical galaxies (Figure 1. left panel), without invoking unrealistically old ages (Park & Lee1997 ). Our models with helium-enhanced subpopulations also predict that the well-known Burstein relation can be explained by the fraction of helium-enhanced subpopulation, the mean age, and the mean metallicity of the underlying stellar populations (Figure 1. right panel).