| Abstract: | Supermassive black holes (SMBHs), with masses of billions of solar masses, are found in the centers of most galaxies, and their growth and energy release mechanisms appear to be closely linked to the galaxies that host them. The different mechanisms that allow for their fast growth, particularly in the first giga-year after the big bang, are not fully understood. I will outline several paths to progress our understanding of these mechanisms, spanning a wide range of physical scales and observational probes. Multi-wavelength campaigns using ALMA and the Hubble Space Telescope suggest that gas-rich galaxy mergers play an important role in early SMBH growth, on large scales. On much smaller scales, I will discuss the prospects for establishing the relevance of super-Eddington accretion onto SMBHs. Finally, new classes of transient phenomena driven by enhanced accretion onto SMBHs may help resolve open questions related to accretion physics, test models of super-Eddington accretion, and reveal how SMBHs turn their accretion “on” and “off”. |