Department of Astronomy


Dynamics of starbursting dwarf galaxies


Federico Lelli

Groningen


The mechanisms that trigger strong bursts of star formation in dwarf galaxies are poorly understood. Blue Compact Dwarfs (BCDs) are nearby starburst galaxies that may hold the key to understand these mechanisms. I will present observational evidence showing that BCDs are different from typical dwarf irregulars. BCDs have strong central concentrations of gas, high central surface brightnesses, and steeply-rising rotation curves, pointing to a strong central concentration of mass. This suggests that the starburst is closely linked with the gravitational potential and the gas concentration. Rotation curve decompositions show that baryons (stars and gas) are dynamically important. I will discuss the implications of these results on the evolution of dwarf galaxies and in particular on the properties of the progenitors and descendants of BCDs. I will also discuss interactions/mergers or cold gas accretion as likely explanations for the triggering of the starburst.