New evidence indicates that there is much hidden matter in galactic nuclei. Quasars are thought to be galaxies with active nuclei, often characterized by nonthermal radio emission and oppositely directed colinear jets. About 1970 Donald Lynden‐Bell and Martin Rees (both Institute of Astronomy, Cambridge, UK) proposed the paradigmatic quasar model: a supermassive black hole surrounded by an accretion disk. In this model a disk overloaded with infalling matter spurts out oppositely directed jets perpendicular to the plane of the disk. “The new work is exciting evidence for how long the quasar phenomenon lasts,” Rees tells us.

This content is only available via PDF.
You do not currently have access to this content.