The High Energy X-ray Probe (HEX-P): Probing the circum-nuclear environment in AGN at extremely low luminosities

HEX-P is a probe-class mission concept that will combine high spatial resolution X-ray imaging (<10 arcsec FWHM) and broad spectral coverage (0.1-150 keV) with an effective area far superior to current facilities (including XMM-Newton and NuSTAR) to enable revolutionary new insights into a variety of important astrophysical problems. A key science goal for HEX-P is to understand the structure and geometry of the circum-nuclear environment surrounding growing supermassive black holes, and how that environment co-evolves with the central engine. In this poster, we will showcase the unprecedented capabilities of HEX-P for studying the dense surroundings of growing supermassive black holes in our cosmic backyard. Due to its uniquely sensitive broadband X-ray coverage, individual spectral studies will distinguish genuine X-ray-faint AGN from obscured AGN at extremely low X-ray fluxes and unabsorbed luminosities whilst considering a broad range of geometries for the intervening material responsible for the obscuration. Complemented by multi-wavelength next-generation all-sky surveys, such studies will be pivotal in deciphering the connection between the AGN obscurer and surrounding host galaxy in some of the highest column density and covering factor regimes ever directly explored in X-rays. The capabilities of HEX-P are hence ideally suited for completing the black hole accretion and host galaxy co-evolution censuses in the nearby Universe, and extremely complementary with next-generation multi-wavelength facilities such as the James Webb Space Telescope, the Vera C. Rubin Observatory and the Nancy Grace Roman Space Telescope. More information on HEX-P, including the full team list, is available at https://hexp.org.