Scientific Seminars

Extraplanar gas and gas accretion in spiral galaxies

F. Fraternali
Universita' di Bologna

2008-05-26    15.00    Merate -

I present evidence that nearby spiral galaxies are accreting a significant mass of gas from the intergalactic medium and are still growing today. Over the last years, it has become clear that nearby spiral galaxies are surrounded by massive haloes of cold gas, with peculiar kinematics. Such extra-planar gas is observed in different types of galaxies including the Milky Way. Its kinematics cannot be explained by stellar feedback (galactic fountains) alone, instead it appears to be the result of interactions between the fountain gas and accreting material. The amount of accretion needed to reproduce the data is of the order of the SFR of the host galaxy.