It is suspected that the ultraviolet ( UV ) upturn phenomenon in elliptical galaxies and extended horizontal-branch stars in globular clusters have a common origin .
An extremely high abundance of helium ( Y \sim 0.4 ) allows for a working hypothesis , but its origin is unclear .
Peng & Nagai ( 2009 ) proposed that primordial helium sedimentation in dark haloes over cosmic timescales may lead to extreme helium abundances in galaxy cluster centers .
In this scenario UV upturn should be restricted to brightest cluster galaxies ( BCGs ) only .
This is a clear and testable prediction .
We present tests of this hypothesis using galaxy clusters from Yoon et al .
( 2008 ) that were detected by both the Sloan Digital Sky Survey and the Galaxy Evolution Explorer Medium Imaging Survey .
Using a new UV classification scheme based on far-UV , near-UV , and optical photometry we found only 5 % of cluster elliptical galaxies show a UV upturn , while 27 % and 68 % are classified as “ recent star-formation ” and “ UV-weak ” ellipticals , respectively .
The data reveal a modest positive dependence of the UV upturn fraction on galaxy velocity dispersion , which is in agreement with the earlier findings of Burstein et al .
( 1988 ) and possibly with the helium sedimentation theory .
However , we do not see any dependency on rank or luminosity of galaxies .
Besides , BCGs do not show any marked difference in UV upturn fraction or strength , which is inconsistent with the prediction .
We conclude that the aforementioned helium sedimentation theory and its inferred environmental effects are not supported by the available data .