2021, Thater, Sabine, Krajnović, Davor, Weilbacher, Peter M., Nguyen, Dieu D., Bureau, Martin, Cappellari, Michele, Davis, Timothy A., Iguchi, Satoru, McDermid, Richard, Onishi, Kyoko, Sarzi, Marc, van de Ven, Glenn

Supermassive black hole masses ( M BH ) can dynamically be estimated with various methods and using different kinematic tracers. Different methods have only been cross-checked for a small number of galaxies and often show discrepancies. To understand these discrepancies, detailed cross-comparisons of additional galaxies are needed. We present the first part of our cross-comparison between stellar-And gas-based M BH estimates in the nearby fast-rotating early-Type galaxy NGC 6958. The measurements presented here are based on ground-layer adaptive optics-Assisted Multi-Unit Spectroscopic Explorer (MUSE) science verification data at around 0 . 6 spatial resolution. The spatial resolution is a key ingredient for the measurement and we provide a Gaussian parametrization of the adaptive optics-Assisted point spread function for various wavelengths. From the MUSE data, we extracted the stellar kinematics and constructed dynamical models. Using an axisymmetric Schwarzschild technique, we measured an M BH of (3 . 6 + 2 . 7-2 . 4 ) × 10 8 M at 3 significance taking kinematical and dynamical systematics (e.g. radially varying mass-To-light ratio) into account. We also added a dark halo, but our data do not allow us to constrain the dark matter fraction. Adding dark matter with an abundance matching prior results in a 25 per cent more massive black hole. Jeans anisotropic models return M BH of (4 . 6 + 2 . 5-2 . 7 ) × 10 8 and (8 . 6 + 0 . 8-0 . 8 ) × 10 8 M at 3 confidence for spherical and cylindrical alignments of the velocity ellipsoid, respectively. In a follow-up study, we will compare the stellar-based M BH with those from cold and warm gas tracers, which will provide additional constraints for the M BH for NGC 6958, and insights into assumptions that lead to potential systematic uncertainty.

2019, Nguyen, Dieu D., Seth, Anil C., Neumayer, Nadine, Iguchi, Satoru, Cappellari, Michelle, Strader, Jay, Chomiuk, Laura, Tremou, Evangelia, Pacucci, Fabio, Nakanishi, Kouichiro, Bahramian, Arash, Nguyen, Phuong M., den Brok, Mark, Ahn, Christopher C., Voggel, Karina T., Kacharov, Nikolay, Tsukui, Takafumi, Ly, Cuc K., Dumont, Antoine, Pechetti, Renuka

We improve the dynamical black hole (BH) mass estimates in three nearby low-mass early-type galaxies: NGC 205, NGC 5102, and NGC 5206. We use new Hubble Space Telescope (HST)/STIS spectroscopy to fit the star formation histories of the nuclei in these galaxies, and use these measurements to create local color–mass-to-light ratio (M/L) relations. We then create new mass models from HST imaging and combined with adaptive optics kinematics, we use Jeans dynamical models to constrain their BH masses. The masses of the central BHs in NGC 5102 and NGC 5206 are both below one million solar masses and are consistent with our previous estimates, ${9.12}_{-1.53}^{+1.84}\times {10}^{5}$ M⊙ and ${6.31}_{-2.74}^{+1.06}\times {10}^{5}$ M⊙ (3σ errors), respectively. However, for NGC 205, the improved models suggest the presence of a BH for the first time, with a best-fit mass of ${6.8}_{-6.7}^{+95.6}\times {10}^{3}$ M⊙ (3σ errors). This is the least massive central BH mass in a galaxy detected using any method. We discuss the possible systematic errors of this measurement in detail. Using this BH mass, the existing upper limits of both X-ray, and radio emissions in the nucleus of NGC 205 suggest an accretion rate lesssim10−5 of the Eddington rate. We also discuss the color–M/Leff relations in our nuclei and find that the slopes of these vary significantly between nuclei. Nuclei with significant young stellar populations have steeper color–M/Leff relations than some previously published galaxy color–M/Leff relations.