AGN outflow is fast-moving gas and plasma pushed out from an active galactic nucleus around a supermassive black hole. In Astrophysics II, it shows how black hole activity can reshape a galaxy.
AGN outflow is the stream of gas, plasma, and particles driven away from the center of a galaxy by an active galactic nucleus. In Astrophysics II, you treat it as one of the main ways a supermassive black hole affects its host galaxy outside the tiny region right around the accretion disk.
The outflow starts near the AGN, where matter falling inward releases huge amounts of energy. That energy can heat nearby gas, push on it with radiation pressure, or help launch a flow through magnetic fields and disk winds. Once the gas is accelerated, it can travel at thousands of kilometers per second, fast enough to disturb the surrounding interstellar medium.
The big idea is feedback. Gas that would normally cool, collapse, and form new stars gets heated, blown outward, or stirred so much that star formation slows down. In some cases, the outflow clears the central region of gas and dust, which changes how bright the nucleus looks and how the galaxy evolves over time.
AGN outflows are not all the same. Some are wide-angle winds that carry mass outward in many directions, while others are tied to narrow jets. Quasars often show especially strong outflows because their AGN are very luminous, while Seyfert galaxies usually show less extreme activity. The exact appearance depends on the black hole’s accretion rate, the geometry of the disk, and the gas around the nucleus.
Observationally, you usually infer an AGN outflow from spectral line shifts, broad absorption features, or disturbed gas motions in imaging and spectroscopy. A blue-shifted absorption line, for example, can mean gas is moving toward you as it escapes the nucleus. That makes AGN outflow a very data-friendly idea in Astrophysics II, because you connect physical models to what telescopes actually record.
AGN outflow shows how a black hole can affect more than just its immediate surroundings. In Astrophysics II, this is one of the clearest examples of galaxy-scale feedback, where energy from a compact object changes the evolution of an entire galaxy.
It matters for star formation because galaxies need cold gas to make new stars. If an outflow removes that gas or heats it so it cannot collapse, the galaxy can shift from active star formation to a quieter phase. That links AGN physics directly to the life cycle of galaxies, not just to the behavior of a single black hole.
It also matters for interpretation. When you look at spectra, line widths, shifts, or unusual emission patterns, AGN outflows can explain why the gas is moving the way it is. In a problem set or data analysis task, you may need to decide whether the observed motion looks like rotation in a disk, inflow toward the center, or outflow away from the nucleus.
This term also connects the small scale and the large scale. The accretion disk and black hole may be tiny compared with the galaxy, but the outflow lets their energy reach thousands of light-years outward. That is a core theme in modern astrophysics.
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Visual cheatsheet
view galleryActive Galactic Nucleus (AGN)
An AGN outflow starts with the AGN itself, so you need to know what powers the central engine. The black hole does not emit the outflow directly, but the energy released by accretion near it creates the conditions that launch winds, radiation-driven gas, or jet-linked flows. If you understand the AGN, the outflow makes much more sense.
Star Formation
AGN outflows can reduce star formation by removing cold gas or keeping it too hot and turbulent to collapse into new stars. That makes this term part of galaxy evolution, not just black hole physics. When you analyze a galaxy with weak or suppressed star birth, an outflow is one possible reason the gas supply got disrupted.
Quasar
Quasars are a high-luminosity kind of AGN, and they often show especially strong outflows. That connection matters because the brighter and more energetic the nucleus is, the more likely it is to drive powerful winds or feedback effects. If you see a quasar in a question, think about more extreme AGN behavior.
magnetohydrodynamics
Magnetohydrodynamics helps explain how ionized gas and magnetic fields interact in AGN environments. In some models, magnetic fields help launch or collimate the flow, especially when the outflow is connected to the accretion disk. This is useful when you are asked why the gas does not just drift outward randomly.
A quiz item might show a spectrum with shifted absorption lines and ask you to identify the motion. Your job is to connect the data pattern to an AGN outflow, then explain whether the gas is being expelled from the nucleus. In a short-answer response, you may need to trace the cause and effect chain: accretion onto the supermassive black hole releases energy, the AGN drives a wind or jet, the wind disturbs the interstellar medium, and star formation can drop.
In image-based questions, look for disturbed central gas, narrow jet-like structures, or signs that the nucleus is clearing out nearby material. In written analysis, use the term when describing galaxy feedback, especially if the prompt asks how black hole activity changes the host galaxy. If your instructor gives a data table, you may also compare speed, mass loss, or luminosity to decide whether the outflow is weak, moderate, or extreme.
AGN outflow is fast-moving gas and plasma expelled from the region around an active galactic nucleus.
It is powered by energy from accretion near a supermassive black hole, often through radiation pressure, magnetic effects, or jets.
The outflow can heat or remove gas from a galaxy, which can slow down star formation.
Quasars usually show stronger outflows than lower-luminosity AGN such as Seyfert galaxies.
You often identify an AGN outflow from spectroscopy, especially from shifted or broadened lines that show gas is moving outward.
AGN outflow is gas and plasma being blown away from the center of a galaxy by an active galactic nucleus. In Astrophysics II, you study it as a feedback process that links black hole activity to galaxy evolution. It can move at thousands of kilometers per second and change the gas supply available for star formation.
An AGN outflow is a broad term for material moving outward from the nucleus, while a jet is usually a narrower, more collimated stream. Some AGN outflows are wind-like, and some are tied closely to jets. If a question shows a wide disturbance in gas, think outflow, but if it shows a tight beam, think jet.
They often use spectroscopy to look for blue-shifted absorption lines, broadened emission lines, or unusual line shapes that show gas is moving away from the nucleus. Imaging can also show disturbed central gas or jet-shaped structures. The key is matching the observed motion to an outward flow rather than simple rotation.
Star formation needs cold, dense gas. AGN outflows can remove that gas, heat it, or stir it so it cannot collapse into new stars. That is why outflows are a major part of feedback in galaxy evolution questions.