The Galactic ecosystem: infall and outflow in the halo
of the Milky Way
by Vanessa Moss (Sydney Uni)
Abstract. The ecosystem of a galaxy is driven by the balance between outflows from the star-forming disk and infall due to interactions with nearby galaxies and the surrounding intergalactic medium. In the case of the Milky Way, the estimated star-forming rate has long been at odds with the detected neutral gas in the halo, raising the important question of where the Milky Way predominantly gets its gas. I will present my thesis results using the Galactic All Sky Survey to catalogue and study anomalous velocity clouds in the Galactic halo. As part of this work, we examined the question of origin vs. environment in interacting clouds using the ATCA and combined our data with a sensitive survey conducted with the Green Bank 40-ft telescope to reveal a halo hidden from most large-scale surveys. Together these results allow us to construct a new picture of the Galactic ecosystem, where the measured star formation rate is in better agreement with halo neutral hydrogen and where infall and outflows may be distinguishable on the basis of their HI properties alone.