X-ray constraints on the local supermassive black hole occupation fraction

Understand

Distinct seed formation mechanisms are imprinted upon the fraction of dwarf galaxies currently containing a central supermassive black hole.

• Seeding by Pop III remnants is expected to produce a higher occupation fraction than is generated with direct gas collapse precursors.
• Chandra observations of nearby early-type galaxies can directly detect even low-level supermassive black hole activity, and the active fraction immediately provides a firm lower limit to the occupation fraction.
• Here, we use the volume-limited AMUSE surveys of ~200 optically-selected early-type galaxies to characterize simultaneously, for the first time, the occupation fraction and the scaling of nuclear X-ray luminosity with stellar mass, accounting for intrinsic scatter, measurement uncertainties, and X-ray limits.