NuSTAR Observations of Accretion Physics

The Nuclear Spectroscopic Telescope Array (NuSTAR) is the first focusing hard X-ray (>10 keV) satellite in orbit, and is providing unprecedented data on energetic phenomena ranging from the solar system to distant quasars. Launched in July 2012, NuSTAR has observed the universe in the 3-79 keV energy region, a spectral window previously limited due to the lack of focusing capabilities and intrinsically high background of other instruments. The NuSTAR observatory has primarily been run as a guest observer facility since 2015, with roughly half of the observatory time being coordinated with other X-ray observatories. In this talk, I will review the role that NuSTAR has played in discovering and understanding accretion power into compact objects. I will describe some of the most relevant scientific results of the last decade including the measuring of black hole spins, detection of fast and ultra-fast outflows, physics of the X-ray corona, characterization of tidal disruption events, constraints of the equation of state in neutron stars, and spectral-timing studies of transient X-ray sources and active galactic nuclei. I will conclude the prospects for future synergies with the new microcalorimeter detectors onboard XRISM and Athena, in tandem with NuSTAR's replacement concept mission HEX-P.