The ecosystem of dwarf galaxies

It remains unclear what physical mechanisms are triggering starbursts in low-mass galaxies and what is the effect of stellar feedback in their shallow potential wells. We study a sample of 18 nearby starburst dwarfs using multi-wavelength data, including interferometric HI observations, HST imaging, and MUSE integral-field spectroscopy. We reach the following results: (1) Starburst dwarfs have more asymmetric HI distributions in the outer parts than typical dwarf irregulars. This suggests that the starburst is triggered by interactions/mergers between dwarf galaxies or cold gas accretion from the IGM. (2) Starburst dwarfs can host regularly rotating HI disks and have gas fractions similar to typical dwarf irregulars, indicating that they did not eject large amounts of gas out of their potential wells. (3) MUSE observations of the famous starburst NGC1705 reveal that the ionized gas is not shock-excited and is not escaping the potential well: gas is pushed gently and ionized by young stars.