Date of Award

3-26-2015

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Applied Science

First Advisor

Marc Seigar

Abstract

In this dissertation, the determination of the masses of supermassive black holes (SMBHs) and the properties of their host spiral galaxies are focused for the purposes of constraining scaling relations and with the aim of understanding the role of SMBHs in the evolution of galaxies. The several techniques in this work as summarized are focused on in Chapter 2. Direct techniques (reverberation mapping, stellar and gas dynamics, maser modeling) and indirect techniques (the SMBH mass versus stellar/gas velocity dispersion relation and the SMBH mass versus spiral arm pitch angle relation) have been used to estimate SMBH masses. Then the measurement of SMBH masses (MBH) for a sample of 61 galaxies are studied by applying the relationships above between the mass and spiral arm pitch angle (P) or host-galaxy stellar/gas velocity dispersion (ó). Also SMBH masses are determined using direct measurements from the literature (i.e., reverberation mapping, stellar/gas dynamics, mass modeling) and a comparison is made. The differences between the resulting SMBH masses are discussed. Then Mid-Infrared (MIR) views of SMBH scaling relations are presented based on a two-dimensional decomposition of Spitzer/IRAC 3.6-micron images. From this, accurate bulge parameters for 41 spiral galaxies have been derived and presented. Spitzer/IRAC provides high-quality imaging data for this sample, and the sensitivity of this instrumentation permits the clear identification of morphological features. These bulge structural parameters are used to determine several SMBH and galaxy morphological scaling relations. These include the SMBH mass - bulge dynamical mass (MBH - Mdyn) relationship, the bulge dynamical mass - spiral arm pitch angle (Mdyn - P) relationship, the SMBH mass - bulge luminosity (MBH - LBulge) relationship, and the bulge luminosity - spiral arm pitch angle (LBulge - P) relationship. In all four cases, strong correlations are found. For the MBH - LBulge, our results agree with previous studies. However, the Mdyn - P relationship and the MBH - LBulge relationship are studied here for the first time. Finally, bulge dynamical and bulge stellar masses for 35 spiral galaxies are estimated by applying the isothermal model and the stellar mass-to-light ratio calibration of Oh et al. (2008) respectively. Thus, we found the kinetic energy of random motions of the corresponding host galaxies by multiplying each mass measurement by the square of the host-galaxy velocity dispersion, i.e., Mdyn ó 2 and M* ó 2 respectively. In conclusion, I have obtained the best linear fit of four scaling relations. The relations, Mdyn - P, M* - P, Mdyn ó2 - P, and M* ó 2 - P, are found to have linear correlation coefficients of 0.823, 0.756, 0.778, and 0.729 respectively. In other words, both the stellar and dynamical masses of bulges correlate well with spiral arm pitch angle. Furthermore, the kinetic energies of random motions in the bulge (whether determined from dynamical or stellar mass) strongly correlate with pitch angle. Hence, spiral arm pitch angle is a parameter that can be used to determine indirect measurements of the bulge dynamical mass, the bulge stellar mass, and the kinetic energy of random motions in the bulge.

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