Ultramassive Black Holes: Fundamental Plane and Coronae

We will measure the X-ray flux and radio continuum of 7 ultramassive BHs (M>3e9) to test competing models of the fundamental plane (FP) of BH accretion. The FP relates the X-ray, radio, and mass of an accreting BH, and demonstrates there is a connection between BH inflow and outflow. The FP is derived mostly from BHs with masses under 2e9. It is not clear if the FP holds for the largest BHs. The 2 ways to create the FP, with only SMBHs OR jointly with SMBHs and stellar BHs, differ by 100 for the largest BHs. Only with Chandra we can separate corona and AGN to determine it. Coronae around huge BHs are critical in limiting feeding so that we can understand the gas supply around and accretion onto the largest BHs.