Galex-derived residual star formation history of elliptical galaxies

Bright early-type galaxies are still forming stars at low-level residual star formation (RSF) mode. The GALEX UV satellite has detected excessive UV flux in > 30% of our volume-limited sample of ∼10 galaxies. The RSF galaxy fraction is higher among the dynamically low-mass sample (RSF-σ relation). We postulate that this is a result of a "critical" MBH - σ relation that regulates residual star formation activities in early type galaxies. Implications are discussed.