Active galaxies
Definition
Active galaxies are galaxies that emit an exceptionally high amount of energy from their cores, often due to the presence of a supermassive black hole. They are characterized by their strong and variable emissions across the electromagnetic spectrum.
5 Must Know Facts For Your Next Test
- Active galaxies include Seyfert galaxies, radio galaxies, and quasars.
- The central engine of an active galaxy is typically a supermassive black hole with an accretion disk.
- Active Galactic Nuclei (AGN) can outshine the entire galaxy in which they reside.
- Jets emitted from active galaxies can travel at relativistic speeds and extend far beyond the host galaxy.
- Observations in multiple wavelengths (radio, optical, X-ray) are crucial for studying active galaxies.
Review Questions
- What is the core engine driving the high energy emissions in active galaxies?
- Name three types of active galaxies.
- Why are observations in multiple wavelengths important for studying active galaxies?
"Active galaxies" appears in:
Study guides (1)
Related terms
Quasar: A very luminous and distant type of active galactic nucleus with strong radio emissions.
Seyfert Galaxy: A type of spiral or irregular galaxy with a bright nucleus showing strong emission lines.
Supermassive Black Hole: A massive black hole found at the center of many galaxies, including those with active nuclei.
