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

We report on IFU measurements of the host of the radio source 4C+37.11. This massive elliptical contains the only resolved double compact nucleus at pc-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 $r_b={1.5}^{\mathrm{\prime }\mathrm{\prime }}$ core and that the stellar velocity dispersion increases inside of a radius of influence $r_{\mathrm{S}\mathrm{O}\mathrm{I}}\approx {1.3}^{\mathrm{\prime }\mathrm{\prime }}$. 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 kpc of the host galaxy.