Characterizing Feedback and Coronal Lines in Active Galactic Nuclei

Supermassive black holes (SMBHs) are thought to lie at the center of virtually every massive galaxy, with a small percentage of them actively accreting matter. These accreting SMBHs, referred to as Active Galactic Nuclei (AGN), likely play a vital role in shaping the evolution of their host galaxy. However, despite decades of intense research, fundamental questions about the formation of SMBHs and the details of AGN-galaxy co-evolution remain unresolved. In this dissertation, I present four spectroscopic studies that aim to address these fundamental questions. Specifically, I examine the influence of galaxy mergers on ionized outflows in a large, robust sample of galaxies. We find that, when the power source of the outflow is controlled for, the merging environment does not have a significant impact on the large-scale ionized outflows traced by [O III] $\lambda$5007 in SDSS. We additionally find that ionized outflows are more common in optically-selected and infrared-selected AGN compared to star-forming galaxies, and that the outflow velocities in AGN are higher compared to outflow velocities in star-forming galaxies. Additionally, I perform follow-up integral field unit (IFU) observations with VLT/MUSE data on a sample of coronal line (CL) emitting galaxies that were first discovered in a large-scale survey of optical CL emission in SDSS. We confirm the previous CL detections, as well as detect new CLs thanks to the enhanced sensitivity and spatial resolution of MUSE. Further, we find that the ionized outflows and CL emission are spatially correlated, as is the radio emission in these galaxies. CL emission is found on kpc-scales, with CL emission found up to $\sim$8 kpc away from the nuclear region. This result is in stark contrast to earlier studies that presumed CL emission would be confined to the central $\sim$pc region of galaxies. We speculate that shocks may be responsible for some of the extended CL emission, but we cannot rule out AGN photoionization. The similar spatial elongations of the CL emission and ionized outflows are suggestive of a deeper connection between the two, which is robustly explored in a statistically significant sample of galaxies. We show that ionized outflows are more common in the presence of optical CLs, and there are several correlations between the CL-emission and outflow properties. These observations show that AGN are capable of significantly impacting the interstellar medium of their host galaxy and subsequently influencing large-scale star formation rates. Finally, I utilize JWST/NIRSpec IFU data to examine a low-mass, low-metallicity dwarf galaxy that is suspected of harboring an intermediate mass black hole (IMBH). This dwarf galaxy has no optical signatures of AGN activity, but has mid-infrared colors that are suggestive of AGN activity. While we do not detect any CL emission in either the JWST/NIRSpec data or the Keck/KCWI IFU data, we nonetheless observe exotic stellar populations consisting of Wolf-Rayet stars and red supergiants in the nuclear region of the galaxy. A steep rising continuum is observed only in the nuclear region, which cannot easily be explained by stellar processes. These observations do not preclude the existence of a deeply embedded IMBH; modeling the infrared emission which CIGALE implies the existence of an IMBH of $\sim$40,000 M_\odot, which is consistent with extrapolations from existing scaling relations from larger mass black holes.

Author

• Matzko, William

• Active Galactic Nuclei
• Coronal lines
• Feedback
• Galaxies
• Galaxy evolution
• Outflows

Identifier

hdl:1920/14723

OAI identifier oai:identifier

oai:MARS:1920/14723