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An Active Galactic Nucleus (AGN) is a compact region at the center of a galaxy that emits an extraordinary amount of energy, often outshining the entire galaxy, due to accretion of matter by a supermassive black hole. AGNs are pivotal in understanding galaxy evolution and the dynamics of supermassive black holes, as they influence star formation and galactic structure through energetic outflows and radiation.
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Supermassive black holes are astronomical objects with masses ranging from hundreds of thousands to billions of times that of the Sun, typically found at the centers of galaxies, including our own Milky Way. They play a crucial role in the formation and evolution of galaxies, influencing their structure and dynamics through gravitational interactions and energetic feedback processes.
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Seyfert galaxies are a class of active galaxies characterized by extremely bright nuclei with spectra that show strong emission lines, indicating the presence of highly ionized gas. They are thought to harbor supermassive black holes at their centers, which power their intense luminosity through accretion of surrounding material.
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The AGN Unification Model proposes that the diverse appearances of Active Galactic Nuclei (AGN) are primarily due to orientation effects relative to the observer, rather than intrinsic differences. This model suggests that all AGNs contain similar central structures, including a supermassive black hole, an accretion disk, and a dusty torus, and their observed properties depend on the line of sight to these components.
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Radiative transfer is the physical process by which energy in the form of electromagnetic radiation is emitted, absorbed, and scattered through a medium. It is critical in understanding phenomena in fields such as astrophysics, atmospheric science, and climate modeling, as it governs the energy balance and information propagation in these systems.
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Dust extinction refers to the absorption and scattering of electromagnetic radiation by dust and gas between an astronomical object and the observer, which causes the object to appear dimmer and alters its apparent color. This phenomenon is critical for accurately measuring the intrinsic brightness and color of celestial objects, and must be accounted for in astronomical observations and models.
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Emission lines are bright lines in a spectrum caused by the emission of photons from atoms or molecules transitioning from higher to lower energy levels. They are crucial in astrophysics and chemistry for identifying the composition and properties of distant celestial objects and various substances through spectroscopic analysis.
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