Abstract

In this thesis, we present a spatially resolved, multi-band dust-attenuation method for correcting the stellar luminosity models used in dynamical supermassive black hole (BH) mass measurements. If uncorrected, dust extinction effects may dominate over other systematic uncertainties when determining the BH mass ($M_\mathrm{BH}$). We expand on a simple dust-attenuation method that treats the circumnuclear disk as a thin dust layer embedded in the galaxy midplane. Using a Multi-Gaussian Expansion, we create a three-dimensional stellar luminosity model to calculate the fractions of stellar light originating in front of and behind the disk along each line of sight. We infer the pixel-by-pixel extinction by fitting Hubble Space Telescope (HST) spectral energy distributions (SEDs) across four to five optical and near-IR filters. From a sample of twelve early-type galaxies (ETGs) with dusty circumnuclear disks, we explore color--color diagnostics to constrain the effect of the extinction law, scattering processes, disk geometry, star formation, nuclear activity, and finite spatial resolution on the observed SEDs. The full dust attenuation modeling method is then fully applied to NGC~3258 and NGC~5193, two ETGs with existing dynamical BH mass measurements and regular circumnuclear disks with little evidence for recent star formation. These data products provide the spatially resolved inputs needed to evaluate and ultimately reduce dust-related systematic uncertainties in gas-dynamical BH mass measurements. This framework is generalized to work on many dust-disk ETGs with multi-band HST imaging.

Degree

College and Department

Computational, Mathematical, and Physical Sciences; Physics and Astronomy

Rights

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