Fang Peng and Daisuke Nagai 2009 ApJ 705 L58 doi:10.1088/0004-637X/705/1/L58
Fang Peng1 and Daisuke Nagai2
Show affiliationsRecent observations with the Galaxy Evolution Explorer (GALEX) show strong unexpected ultraviolet (UV) excess in the spectrum of brightest cluster galaxies (BCGs). It is believed that the excess UV signal is produced by old and evolved core-He burning stars, and the UV flux strength could be greatly enhanced if the progenitor stars have a high value of He abundance. In this work, we propose that the sedimentation process can greatly enhance the He abundance in BCGs. Our model predicts that the UV flux strength is stronger in more massive, low-redshift, and dynamically relaxed BCGs. These predictions are testable with the current generation of GALEX+SDSS observations.
diffusion; galaxies: clusters: general; galaxies: elliptical and lenticular, cD; ultraviolet: galaxies
95.85.Mt Ultraviolet (10–300 nm)
98.62.Py Distances, redshifts, radial velocities; spatial distribution of galaxies
98.62.Lv Stellar content and populations; radii; morphology and overall structure
Issue 1 (2009 November 1)
Received 2009 August 5, accepted for publication 2009 September 30
Published 2009 October 12
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