Radio jet driven outflows : an investigation of extended emission line regions around radio loud AGNs

Shih, Hsin Yi
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[Honolulu] : [University of Hawaii at Manoa], [August 2014]
Galactic-scale outflows play an important role in galaxy evolution. They serve to regulate the star formation rates and suppress the growth of supermassive black holes. A significant fraction of active galactic nuclei (AGNs) possess powerful radio jets capable of driving such large-scale outflows. Having a good grasp of the physical properties of the outflows is essential for understanding the impact they can have on their environment. The first part of this thesis aims to characterize a large sample of radio jet-driven outflows. I selected a sample of 80 radio-loud AGNs and observed them using an integral field spectrograph. The resulting data map the flux distribution and the kinematic structure of any detected outflow, which allowed us to estimate the total mass, mass outflow rate, and 3-D morphology of the outflow. Despite circumstantial evidence that supports a direct causal link between the jets and the outflows, the most luminous and extended outflow systems do not show any evidence of interaction with the radio jets. I observed the outflow systems from 8 very young radio sources, which are more likely to show evidence of direct jet-cloud interaction. I found that at these early stages, the outflows have morphologies and velocity gradients that are well aligned with the corresponding radio axes, unlike the outflows associated with the more evolved radio sources. To further investigate the early stage of the outflows, I performed a detailed analysis of a very young and compact outflow from 3C 48, a young radio-loud quasar. Emission-line ratios of this outflow suggest that it is significantly denser and more enriched with heavy elements when compared with the outflows around more evolved radio sources. If a larger sample can con rm this distinction, it will serve as a strong constraint for the evolutionary model of radio jet-driven outflows.
Ph.D. University of Hawaii at Manoa 2014.
Includes bibliographical references.
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