3 min read•Last Updated on August 9, 2024
Active galactic nuclei (AGN) wield immense power over their host galaxies. Through radiative and mechanical feedback, they shape galactic evolution, regulating star formation and gas flows. This dynamic interplay between AGN and their surroundings is crucial for understanding galaxy formation.
AGN feedback mechanisms create a delicate balance in galactic ecosystems. By heating gas, driving outflows, and altering the interstellar medium, AGN influence star formation rates and galaxy growth. This feedback loop connects the growth of supermassive black holes to their host galaxies' evolution.
Frontiers | Probing the Gas Fueling and Outflows in Nearby AGN with ALMA View original
Is this image relevant?
Frontiers | AGN Feedback and Its Quenching Efficiency View original
Is this image relevant?
Frontiers | The Many Routes to AGN Feedback View original
Is this image relevant?
Frontiers | Probing the Gas Fueling and Outflows in Nearby AGN with ALMA View original
Is this image relevant?
Frontiers | AGN Feedback and Its Quenching Efficiency View original
Is this image relevant?
1 of 3
Frontiers | Probing the Gas Fueling and Outflows in Nearby AGN with ALMA View original
Is this image relevant?
Frontiers | AGN Feedback and Its Quenching Efficiency View original
Is this image relevant?
Frontiers | The Many Routes to AGN Feedback View original
Is this image relevant?
Frontiers | Probing the Gas Fueling and Outflows in Nearby AGN with ALMA View original
Is this image relevant?
Frontiers | AGN Feedback and Its Quenching Efficiency View original
Is this image relevant?
1 of 3
Active Galactic Nuclei (AGN) are extremely bright regions at the centers of some galaxies, powered by supermassive black holes that accrete matter at an incredible rate. The intense energy output from these regions is due to various processes, including the gravitational energy released as matter falls into the black hole, making AGN key players in understanding galaxy formation and evolution.
Term 1 of 20
Active Galactic Nuclei (AGN) are extremely bright regions at the centers of some galaxies, powered by supermassive black holes that accrete matter at an incredible rate. The intense energy output from these regions is due to various processes, including the gravitational energy released as matter falls into the black hole, making AGN key players in understanding galaxy formation and evolution.
Term 1 of 20
Active Galactic Nuclei (AGN) are extremely bright regions at the centers of some galaxies, powered by supermassive black holes that accrete matter at an incredible rate. The intense energy output from these regions is due to various processes, including the gravitational energy released as matter falls into the black hole, making AGN key players in understanding galaxy formation and evolution.
Supermassive Black Hole: A type of black hole with masses ranging from millions to billions of solar masses, typically found at the centers of galaxies, including those hosting AGN.
Quasar: A highly luminous type of AGN that emits massive amounts of energy, often outshining entire galaxies, and is observed at very high redshifts.
Accretion Disk: A structure formed by diffused material in orbital motion around a central body, such as a black hole, where friction causes the material to heat up and emit radiation.
Mechanical feedback refers to the process by which physical forces or motions in a system lead to changes in that system's behavior or state. In astrophysical contexts, this feedback can influence star formation and galaxy evolution by regulating the energy and material outflows from stars, which in turn affect the surrounding interstellar medium and future star formation activity.
Star Formation: The process by which dense regions within molecular clouds in galaxies collapse under gravity to form stars.
Supernova Feedback: The energy released during a supernova explosion that can inject momentum and energy into the surrounding medium, impacting star formation rates.
Active Galactic Nucleus (AGN): A highly energetic region at the center of some galaxies, powered by a supermassive black hole, which can drive strong outflows and jets affecting the host galaxy's evolution.
Gas flows refer to the movement of gas, often in the form of hydrogen, helium, or other elements, through various regions of space and within galaxies. This movement is essential for understanding how galaxies evolve over time as it influences star formation, chemical enrichment, and the dynamics of galaxy interactions. Gas flows can be driven by gravitational forces, radiation pressure, or supernova feedback, leading to complex feedback mechanisms that play a critical role in galaxy co-evolution.
Supernova Feedback: The process by which the energy and material expelled during a supernova explosion can influence surrounding gas and dust, potentially triggering new star formation.
Galaxy Mergers: The event when two or more galaxies collide and combine, often resulting in significant gas flows that can enhance star formation and alter the structural dynamics of the galaxies involved.
Star Formation Rate: A measure of the amount of new stars being formed in a galaxy over a specific period, which is heavily influenced by the availability and flow of gas within that galaxy.
AGN feedback refers to the energetic influence of active galactic nuclei (AGNs) on their host galaxies, which can regulate star formation and affect the overall evolution of galaxies. This process involves the release of energy and momentum from accreting supermassive black holes at the centers of galaxies, shaping their environment through various feedback mechanisms. It plays a critical role in understanding how galaxies co-evolve with their central black holes and the surrounding interstellar medium.
Active Galactic Nucleus (AGN): A compact region at the center of a galaxy that emits enormous amounts of energy, powered by accretion of matter onto a supermassive black hole.
Star Formation Rate (SFR): The rate at which new stars are being formed in a galaxy, influenced by factors such as gas density and feedback processes.
Supermassive Black Hole (SMBH): A black hole with a mass ranging from millions to billions of solar masses, typically found at the center of galaxies and associated with AGNs.
Outflows refer to the streams of material, such as gas and dust, that are expelled from a celestial object like a star or a galaxy. These outflows play a crucial role in various astrophysical processes, impacting star formation, the evolution of galaxies, and the dynamics of interstellar medium. They can be driven by mechanisms like stellar winds, supernova explosions, or active galactic nuclei, influencing both the immediate environment and larger scale galactic structures.
Stellar Winds: Streams of charged particles ejected from the outer layers of a star, contributing to the outflow of material in the vicinity of stars.
Supernova: An explosive death of a star that releases an enormous amount of energy and material into space, significantly contributing to outflows and enriching the interstellar medium.
Galactic Feedback: The process by which energy and material released from stars and supermassive black holes affect the surrounding galaxy, often seen in relation to outflows.
The interstellar medium (ISM) is the matter that exists in the space between stars in a galaxy, consisting of gas, dust, and cosmic rays. This material plays a crucial role in the formation and evolution of stars and galaxies, acting as both a reservoir for star formation and a medium through which energy and matter are exchanged. The ISM is influenced by galactic magnetic fields and has significant interactions with cosmic rays, impacting the overall dynamics and chemistry of the galaxy.
Cosmic Rays: Highly energetic particles, primarily protons, that travel through space at nearly the speed of light and originate from various astrophysical sources, including supernovae and active galactic nuclei.
Nebula: A giant cloud of gas and dust in space, often a site for new star formation, which contributes to the interstellar medium and its characteristics.
Magnetic Fields: Invisible fields produced by electric currents or magnetic materials that influence the movement of charged particles in the interstellar medium and play a role in star formation processes.
Radiative feedback refers to the processes by which the energy emitted by stars and other celestial objects affects their surrounding environments and influences subsequent star formation and galaxy evolution. This interaction plays a crucial role in regulating the balance of energy within galaxies, affecting temperature, density, and the dynamics of gas clouds, thereby contributing to the co-evolution of galaxies and their stellar populations.
Star Formation: The process by which dense regions within molecular clouds collapse under gravity to form new stars.
Feedback Mechanism: A process in which the output of a system influences its own operation, often enhancing or dampening specific behaviors within that system.
Galaxy Evolution: The study of how galaxies change over time, including their structure, star formation rates, and interactions with other galaxies.
Radiation pressure is the force exerted by electromagnetic radiation on a surface, resulting from the momentum carried by photons. This phenomenon plays a crucial role in various astrophysical processes, including the dynamics of stars and the interaction between radiation and matter, influencing galaxy evolution and feedback mechanisms.
Photon: A photon is a quantum of electromagnetic radiation, which carries energy and momentum, and is fundamental to understanding radiation pressure.
Supernova: A supernova is a powerful explosion of a star at the end of its life cycle, which can significantly impact its surrounding environment through shock waves and radiation pressure.
Feedback Mechanism: Feedback mechanisms are processes that can amplify or dampen effects in astrophysical systems, such as how radiation pressure can influence star formation rates and the growth of galaxies.
Compton heating refers to the process by which high-energy photons, such as X-rays or gamma rays, collide with electrons, resulting in the transfer of energy from the photons to the electrons. This energy transfer can increase the temperature of the gas in which these interactions occur, playing a crucial role in the thermal dynamics of various astrophysical environments, especially in feedback mechanisms that influence galaxy evolution.
Feedback Mechanisms: Processes that influence the growth and evolution of galaxies through interactions between stars, gas, and dark matter, often affecting star formation rates.
X-ray Binaries: A type of binary star system where one star is a compact object, such as a neutron star or black hole, that emits X-rays due to the accretion of material from its companion star.
Cosmic Microwave Background (CMB): The afterglow radiation from the Big Bang, filling the universe and providing a snapshot of the early universe's temperature and density fluctuations.
Photoionization is the process in which an atom or molecule absorbs a photon and subsequently ejects one or more of its electrons, resulting in the formation of a positively charged ion. This phenomenon plays a critical role in shaping the characteristics of the interstellar medium and influences the feedback mechanisms in galaxy co-evolution. It is especially important in regions with high-energy radiation, such as around young stars, where it can lead to significant changes in the surrounding gas and dust.
Ionization Energy: The minimum energy required to remove an electron from an atom or ion, influencing how readily a substance can undergo photoionization.
H II Regions: Clouds of ionized hydrogen in space, typically formed around young, hot stars where photoionization occurs, significantly affecting star formation and the evolution of galaxies.
Radiative Feedback: The process by which radiation from massive stars impacts their surroundings, influencing star formation rates and the dynamics of gas within galaxies.
Galaxy clusters are large groups of galaxies held together by gravity, consisting of hundreds to thousands of individual galaxies, along with dark matter and hot gas. These clusters serve as important laboratories for studying galaxy formation and evolution, revealing the effects of feedback mechanisms on their development, the role they play in large-scale structure formation, and how they fit into the cosmic web.
Dark Matter: A form of matter that does not emit or absorb light, making it invisible and detectable only through its gravitational effects on visible matter and radiation.
Supernova Feedback: The process by which energy and material expelled from supernovae influence star formation and the interstellar medium in galaxies.
Cosmic Web: The large-scale structure of the universe, characterized by a network of filaments of galaxies and galaxy clusters separated by vast voids.
Cooling flows refer to the process in which hot gas in galaxy clusters loses energy and cools down, leading to a flow of cooler gas towards the center of the cluster. This phenomenon is essential in understanding how galaxies evolve, as the cooling gas can fuel star formation and affect the dynamics of the cluster. The interaction between cooling flows and feedback mechanisms also plays a critical role in the co-evolution of galaxies and their surrounding environments.
Hot Gas: The high-temperature gas found in the intracluster medium, primarily composed of ionized hydrogen and helium, which emits X-rays due to thermal Bremsstrahlung radiation.
Feedback Mechanisms: Processes that regulate star formation and the growth of supermassive black holes, including energy and momentum input from stellar winds and supernova explosions.
Star Formation Rate: The rate at which new stars are formed in a galaxy, often influenced by the availability of cool gas from processes like cooling flows.
Black hole-galaxy co-evolution refers to the interconnected growth and development of supermassive black holes and their host galaxies over cosmic time. This relationship implies that the formation and evolution of galaxies are influenced by the presence and activity of black holes, while black holes themselves are shaped by the characteristics and dynamics of their surrounding galaxies. These interactions highlight how feedback mechanisms, such as energy output from black hole accretion and galactic winds, play a critical role in regulating star formation and galaxy morphology.
Supermassive Black Hole: A black hole with a mass ranging from hundreds of thousands to billions of solar masses, typically found at the centers of galaxies.
Active Galactic Nucleus (AGN): A compact region at the center of a galaxy that emits an enormous amount of energy, often associated with supermassive black holes that are actively accreting material.
Galaxy Formation: The process by which matter collapses under gravity to form galaxies, influenced by various factors including dark matter, gas dynamics, and feedback processes from stars and black holes.
Starbursts are regions of intense star formation within galaxies, characterized by the rapid birth of massive stars over a short period of time. This phenomenon often occurs when galaxies interact or merge, triggering gravitational instabilities that compress gas and dust, leading to a surge in star creation. The resulting energy output from these massive stars can significantly influence the surrounding environment and contribute to galaxy evolution.
H II regions: Clouds of ionized hydrogen gas surrounding newly formed massive stars, which are indicators of active star formation.
galaxy merger: The process where two or more galaxies collide and combine, often leading to bursts of star formation due to gravitational interactions.
supernova: The explosive death of a massive star, which can occur in a starburst region and return heavy elements to the interstellar medium.
Mergers refer to the process where two or more galaxies combine to form a single, larger galaxy. This process is a key mechanism in galaxy evolution and has significant implications for the development of quasars, the interaction of galaxies, and the broader cosmic structure.
Galaxy Cluster: A large structure that consists of hundreds to thousands of galaxies bound together by gravity.
Active Galactic Nuclei (AGN): The extremely bright and energetic centers of some galaxies, powered by supermassive black holes accreting material.
Dark Matter: An unknown form of matter that does not emit light or energy, making it invisible and detectable only through its gravitational effects on visible matter.
AGN heating refers to the process by which Active Galactic Nuclei (AGNs) release immense amounts of energy, impacting their surrounding environments, particularly in galaxies. This energy is produced as matter falls into supermassive black holes, resulting in the emission of radiation across various wavelengths. AGN heating plays a crucial role in regulating star formation and influencing the evolution of galaxies over cosmic time.
Active Galactic Nucleus (AGN): A region at the center of some galaxies that is exceptionally bright and energetic due to the presence of a supermassive black hole actively accreting material.
Feedback Mechanism: Processes through which the energy and materials from stars or AGNs influence their surrounding environment, affecting star formation and galaxy evolution.
Supermassive Black Hole: A type of black hole found at the center of galaxies with masses millions to billions times that of the Sun, often associated with AGNs.
Bimodality in galaxy populations refers to the existence of two distinct groups of galaxies, typically separated by their properties such as color, morphology, and star formation rates. This concept highlights the dichotomy between early-type galaxies, which are generally red, elliptical, and passively evolving, and late-type galaxies, which are blue, spiral, and actively forming stars. Understanding this bimodal distribution is essential for studying how galaxies evolve over time and how they interact with their environments.
Hubble Sequence: A classification scheme for galaxies developed by Edwin Hubble that categorizes them into different types based on their morphology, including elliptical, spiral, and irregular galaxies.
Star Formation Rate (SFR): The rate at which new stars are formed in a galaxy, which significantly influences its overall properties and evolutionary path.
Galaxy Mergers: Events in which two or more galaxies collide and combine, often resulting in changes to their morphology and star formation activity.