The Central Kinematics and Black Hole Mass of 4C+37.11

We report on integral field unit (IFU) measurements of the host of the radio source 4C+37.11. This massive elliptical contains the only resolved double compact nucleus at parsec-scale separation, likely a bound supermassive black hole binary (SMBHB). i-band photometry and GMOS-N IFU spectroscopy show that the galaxy has a large r _b = 1.″5 core and that the stellar velocity dispersion increases inside of a radius of influence r _SOI ≈ 1.″3. Jeans Anisotropic Modeling analysis of the core infers a total SMBHB mass of ${2.8}_{-0.8}^{+0.8}\times {10}^{10}{M}_{\odot }$ , making this one of the most massive black hole systems known. Our data indicate that there has been significant scouring of the central kiloparsec of the host galaxy.