Who first described Seyfert galaxies?
Q: Who first described Seyfert galaxies?
A: Carl Seyfert first described them in 1943.
Q: What are the two main types of active galaxies?
A: The two main types of active galaxies are Seyfert galaxies and quasars.
Q: What makes Seyfert galaxies different from quasars?
A: Unlike quasars, their host galaxies are clearly visible in Seyfert galaxies. They are also closer and less luminous than quasars.
Q: How much of all galaxies are made up by Seyferts?
A: About 10% of all galaxies are made up by Seyferts.
Q: What is believed to be the source of the observed ultraviolet radiation in these objects?
A: It is believed that the accretion discs surrounding supermassive black holes at their centers are the source of the observed ultraviolet radiation in these objects.
Q: How can we analyse the material surrounding a Seyfert galaxy?
A: Ultraviolet emission lines and absorption lines can be used to analyse the material surrounding a Seyfert galaxy.
Q: What does a typical Seyfert galaxy look like when seen in visible light?
A: When seen in visible light, most Seyfert galaxies look like normal spiral galaxies.
