Title: Supermassive Black Holes and the Warm Ionized Gas in Early-type Galaxies

Speaker: Pro. Renbin Yan

Time and place: 14:00-15:00, April 1 (Monday), 2013, Lecture Hall /CAA/NO.955,JianChuan Road,MinHang

Abstract:

Supermassive black holes at the centers of massive galaxies has often been invoked to provide the feedback needed to quench star formation or to maintain a low star formation rate in early-type galaxies. To test this, we need to survey their accretion rates and modes. On the other hand, the majority of massive elliptical or lenticular galaxies contain significant amount of weakly ionized gas displaying LINER-like line ratios, which is often assumed to be photoionized by the radiation produced by accreting supermassive black holes. However, I will show in this talk that the true ionizing source for this gas cannot be the accreting black hole but is probably an elusive population of hot evolved stars distributed throughout each galaxy. This finding raises important questions about the role of supermassive black holes in galaxy evolution. More importantly, it opens new windows for studying the origin of the cold and warm gas in these massive galaxies.