Astronomy Tea Talk

Galaxy mergers are inevitable in the mass assembly history of galaxies and their supermassive black holes. In merger simulations, gravitational torques induce rapid star formation and black hole accretion in both galaxies by driving gas deep into their nuclei. Such a phenomenon has been observed in a number of merging galaxies. However, it was unclear how well the simulations match the observations, quantitatively. I will talk about two experiments designed to address this issue. First, through a systematic search of kpc-scale binary active galactic nuclei, I will show that mergers enhance black hole accretion at a level consistent with simulations. Secondly, through detailed mid-IR spectroscopy of a complete sample of luminous infrared galaxies at z ~ 0.7, I will show that black hole accretion during intensive star formation allows merging galaxies to evolve along the fundamental scaling relation between galaxy mass and black hole mass.