BHS SHAPING GALAXIES · Black holes altering galaxy evolution: how to find them?

A major challenge in our understanding of the Universe is that cosmological simulations of galaxy formation and evolution fail to reproduce the mass distribution of present-day galaxies, producing more massive galaxies than those observed. Black holes are claimed capable of solving the problem by accelerating gas and expelling it out of galaxies through radiation pressure, plasma jets, or accretion-disk winds. Recent observations confirmed the existence of outflows carrying more molecular gas than the gas that forms new stars in ~10 nearby galaxies. The phenomenon's frequency is nonetheless unclear. Our goal is to determine, for the first time, how frequently do black holes in the local Universe drive fast, massive outflows that can suppress star formation and affect the evolution of their galaxies. To discover new outflows, we will (a) determine the properties of the outflowing gas in nearby prototype galaxies observed with the Herschel Space Telescope, Institut de Radio-Astronomie Millimetrique Interferometer, Sub-Millimeter Array, and Very Large Telescope, (b) run magnetohydrodynamic simulations to identify the most likely driving mechanism and to quantify the amount by which star formation is suppressed/enhanced in each case, and (c) initiate a large-scale query for new molecular gas outflows in the archive of the largest infrared space mission, Herschel. Our project will set the foundations for similar future queries in the archive of the largest mm ground-based facility, the Atacama Large Millimeter Array, which will probe the coldest gas component of these new flows.