Program: GN-2024B-Q-312

The M-sigma relation (between a galaxy's supermassive black hole (SMBH) mass and its stellar velocity dispersion) is used - directly, or via its calibration of reverberation mapping results - to constrain the properties and evolution of SMBHs and active galactic nuclei (AGN) at all redshifts. This relationship, based on heterogeneous measurements and techniques in ~100 nearby galaxies, is plagued by measurement errors, systematics, and selection biases. When available, gas- and stellar-dynamic determinations often give significantly different results for the SMBH mass of a given galaxy. We propose GMOS-IFU observations to determine high precision stellar-dynamic SMBH masses in three galaxies selected based on their photon ring size of respective black holes. The goal of this pilot is to commence a study of systematic biases of different SMBH measurement techniques under varying assumptions, and varying resolution and SNR thresholds, which will be fundamental in curating a sample to be followed by the Event Horizon Telescope.