0 Assigned ID: 6824 ----- Attempting Submission 1 (Thu Apr 10 23:17:35 GMT 2025) ----- NGC 4486B, a compact elliptical close to M87, has a double nucleus similar to that in M31 that is probably an eccentric nuclear stellar disk. We found a supermassive black hole (SMBH) of mass ~3.5-4.8x10^8Msun (7-16% of the stellar mass) offset by 6 pc from the galaxy's photometric center. This proposal aims to build the first eccentric nuclear disk model for NGC 4486B fitted to archival HST imaging and STIS and NIRSpec kinematics to measure the disk's mass, inclination, and precession rate. The SMBH has a velocity of +144 km/s relative to the galactic center, likely due to a gravitational wave (GW) recoil kick from a black hole (BH) merger that also scoured out the galaxy's large, shallow core. Our model will also yield the fraction of counter-rotating orbits, which depends on the BH's kick velocity and disk circular velocity and determines the disk's longevity. Using the highly efficient phi-GPU software, we will run direct N-body simulations of the post-kick evolution of circular nuclear disks embedded in the N-body model of NGC 4486B constrained by HST and JWST data. These simulations will provide insights into the formation and evolution of eccentric nuclear stellar disks surrounding SMBH. Our modeling code and simulations will be made public and are applicable to future HST, JWST, and ELT observations of double nuclei in e.g., M31, VCC128, VCC1107, and FCC208. Insights gained from this study will inform our understanding of the formation and dynamical evolution of SMBH and their nuclear disks and have implications for interpreting observations by LISA, NANOGrav, and other GW observatories. Monica Valluri (PI) is a galactic dynamicists with significant experience modeling galactic nuclei using space space based and ground-based photometriy and kinematics. She is also experienced with simulating the stellar dynamics around SMBH. Behzad Tahmesebzadeh is a postdoc with experience in orbit superposition (Schwarzschild) modeling. He build the first Schwarzschild model of a barred galaxy and is responsible for the modeling of NIRSpec IFU kinematics of 18 Virgo cluster dwarfs observed in Cycle I (including the models of NGC 4486B presented in the proposal. Fazeel Khan is an expert on direct N-body simulations of SMBH including simulations of binary BHs in galactic nuclei. He has significant prior expertise with the phi-GPU software to be used in this project. Eugene Vasiliev is a galactic dynamicist with significant experience in simulating and modeling galactic nuclei with SMBH. He is also the primary developer of FORSTAND the Schwarzschild modeling code to be used/modified for this project. Kelly Holley-Bockelmann is an expert on galactic dynamics with significant experience on the evolution of black hole binaries. She is also a member of the LISA collaboration. Supermassive Black Holes and Active Galaxies Galaxies 0 false false false true false false false SUPPORTED