A Binary Model for the UV-upturn of Elliptical Galaxies

By Zhanwen Han, P. Podsiadlowski, A. Lynas-Gray, Kevin Schawinski. Proceedings of the International Astronomical Union, 2006

152 citations recorded by the source corpus.

Abstract The discovery of an excess of light in the far-ultraviolet (UV) in 1969 in elliptical galaxies was a major surprise. While it is now clear that this UV excess (UV-upturn) is probably caused by an old population of helium-burning stars. Han et al. (2002, 2003) proposed a binary model for the formation of hot subdwarfs (helium burning stars) and the model can reproduce the observations in our Galaxy. By applying the binary model to the study of evolutionary population synthesis, we have obtained an a priori model for the UV-upturn of elliptical galaxies. The model shows that the UV-upturn is most likely resulted from binary interactions and it is universal (not very much metallicity-dependant) in ellipticals. This has major implications for understanding the evolution of the UV-upturn and elliptical galaxies in general; contrary to previous postulates, it implies that the UV-upturn is not a sign of age, but could be a potentially powerful indicator for a recent minor burst of star-forming activity.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/30836916987b53274cbdef049f1dcb12ae3da9b9

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In Astronomy and Astrophysics

1. C. Conroy
2. L. Hernquist
3. P. Hopkins
4. J. Brinchmann
5. A. Fontana
6. R. Dav'e
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In Instrumentation

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7. L. Pentericci
8. L. Hernquist

Citations in the corpus

• Fitting the integrated spectral energy distributions of galaxies (2010, background): “While this causes little difference in most cases, in some situations (such as where blue stragglers may dominate) recent binary stellar population models may be more suitable (Han et al. 2007).”
• Spectral population synthesis including massive binaries (2009, background): “We also note that Han et al. (2007) incorporated binary evolution of lowmass stars to explain the observed UV flux in some elliptical galaxies.”
• Galaxies with Wolf-Rayet signatures in the low-redshift Universe. A survey using the Sloan Digital Sky Survey (2008, background): “The effect of binaries on the evolution of massive stars has been studied quite extensively although the number of relatively poorly known parameters have meant that it is rarely included in population synthesis codes (see Han et al. 2007; Van Bever & Vanbeveren 2003, for two exceptions).”
• Star formation and mass assembly in high-redshift galaxies (2009, background): “Moreover, the UV-upturn atλ shortward of 2500 Å (e.g., Han et al. 2007), especially in elliptical galaxies, can potentially bias the SFR estimate at very low redshift.”