The Radio–X-Ray–BH-Mass Plane for the Smallest Supermassive Black Holes

The fundamental plane relates the X-ray luminosity, radio luminosity, and mass of accreting BHs and demonstrates an intimate connection between BH inflow and outflow. Existing data are mostly from SMBHs with Mbh > 10^7. It is not clear whether the plane holds below this. Small SMBHs are critical to our understanding of BH formation and growth as well as feedback in the early Universe. We propose to survey all known BHs with mass estimates Mbh < 10^6.2 that have no CXO or XMM observations, but have VLA FIRST radio detections. With modest CXO exposures and new EVLA observations of these 7 sources plus 4 archival sources, we can test the robustness of the plan at low-mass and whether accretion properties scale from stellar BHs thus testing how BH feedback scales with mass and accretion rate.