The Origin and Evolution of Extragalactic Radio Sources and their Impact on Galaxy Formation and Evolution

点击翻译按钮获取中文摘要

Supermassive black holes located in the center of a galaxy (an Active Galactic Nucleus, AGN) can be fueled by the accretion of gas, producing extremely energetic phenomenon such as luminous hot disks of accreting gas and powerful outflows of relativistic plasma and magnetic fields, called jets.  The observed relation between mass of the supermassive black hole and the host galaxy  indicates that galaxies and their central black holes must co-evolve under the influence of a feedback mechanism which creates the proportionality in their masses.  It has been recently recognized that powerful AGN-driven outflows directly affect the evolution of galaxies, with the kinetic energy in the jets heating the galaxy's gas and expelling it from the central bulge regions. This in turn influences galaxies star formation histories, mediating the relationship between host galaxy and central supermassive black hole shaping the high luminosity end of the galaxy luminosity function. The "AGN feedback effect" is now routinely incorporated into numerical simulations of galaxy evolution. However, major uncertainties remain about how AGN interact with the forming and evolving host galaxies and their environments, including the time scales and energetics of the feedback. It is important to resolve these uncertainties if we are to truly understand the links between galaxy evolution and AGN activity, and thereby accurately incorporate the AGN feedback effect into galaxy formation and evolution models. This question has been identified as a critical issue for astronomy and astrophysics by the most recent decadal surveys in both Canada and the USA. My long term goals are to understand the physical processes through which energy is deposited in the host galaxy due to the expanding radio source, including the spatial scales, time scales, and total energy. Our short term goals for this proposal are to investigate compact radio sources to probe interactions between jets and their interstellar medium (ISM) on sub-kpc to kpc scales. These radio sources are well matched to the size of the ISM and should have maximum impact on the star formation of the host galaxy in either a positive or negative sense. My previous work has shown that the jets in compact radio sources interact strongly with gas clouds, can trigger star formation in some cases, and can also drive shocks into the hot component of the ISM. Thus, the CSS sources probe the time scales and energetics which are needed to understand radio source feedback. The impact of this research will be to greatly improve our understanding of how the formation and evolution of galaxies is affected by their supermassive black holes. The requested funding will provide support for two graduate students and summer research for an undergraduate at U Manitoba for 5 years. The students will develop the skills necessary to work in teams, think independently, communicate effectively, and carry out front-line scientific research.