AGN Outflow

Definition

AGN outflow refers to the high-velocity winds of gas and plasma that are expelled from the vicinity of an active galactic nucleus (AGN), which is powered by a supermassive black hole at the center of a galaxy. These outflows play a significant role in regulating star formation and the evolution of galaxies, as they can remove gas from the surrounding region, impacting the availability of material needed for new stars to form and influencing the galactic environment.

5 Must Know Facts For Your Next Test

1. AGN outflows can reach speeds of up to thousands of kilometers per second, significantly affecting the interstellar medium of their host galaxies.
2. These outflows are believed to be driven by radiation pressure from the intense energy output of the AGN, as well as by jets emitted from the accretion disk surrounding the supermassive black hole.
3. The impact of AGN outflows can help regulate star formation within galaxies by expelling gas that would otherwise contribute to new star formation.
4. Different types of AGN show varying outflow characteristics; for example, quasars typically exhibit stronger outflows than Seyfert galaxies.
5. Observations suggest that AGN outflows can also influence the chemical composition and dynamics of their host galaxies, contributing to feedback processes in galactic evolution.

Review Questions

• How do AGN outflows influence the star formation processes within their host galaxies?
  • AGN outflows influence star formation by expelling gas from the galactic environment. As these high-velocity winds push material away, they reduce the amount of gas available for star formation. This feedback mechanism can either inhibit star formation by removing necessary components or create turbulence that may trigger localized star formation in certain regions.
• Compare the characteristics and effects of AGN outflows in quasars versus Seyfert galaxies.
  • Quasars generally exhibit more powerful and energetic AGN outflows compared to Seyfert galaxies. The higher luminosity of quasars results in stronger radiation pressure, driving more substantial winds. While Seyfert galaxies do produce outflows, they are typically less intense and have different effects on their surroundings, often leading to less dramatic changes in their interstellar medium and star formation rates.
• Evaluate the role of AGN outflows in shaping the evolutionary paths of galaxies across cosmic time.
  • AGN outflows play a crucial role in shaping galaxy evolution by acting as a feedback mechanism that regulates both star formation and gas dynamics. Throughout cosmic time, these outflows can remove gas from galaxies, thereby suppressing star formation during critical periods of growth. Additionally, they can enrich the intergalactic medium with heavy elements produced in stars. This complex interplay helps determine how galaxies evolve, affecting their mass, structure, and ultimate fate in the universe.

Related terms

Active Galactic Nucleus (AGN): A compact region at the center of a galaxy that is extremely bright and energetic, believed to be powered by accretion of material onto a supermassive black hole.

Quasar: An exceptionally luminous and distant active galactic nucleus, which emits enormous amounts of energy, often outshining entire galaxies.

Star Formation: The process by which dense regions within molecular clouds collapse under their own gravity to form new stars, influenced by the surrounding environment.