0 the centre of a galaxy (= group of stars) that is very far away, producing large amounts of energy --
There were also serious concerns regarding the idea of cosmologically distant quasars.
Quasars show the locations where massive black holes are growing rapidly (via accretion).
This would mean that a quasar varying on a time scale of a few weeks can not be larger than a few light-weeks across.
Gravitational lensing was first observed in 1979, in the form of a quasar lensed by a foreground galaxy.
This pair provide evidence for the theory that quasars are switched on by galactic collisions.
This early burst of star formation is thought to have made a protogalaxy's luminosity comparable to a present day starburst galaxy or a quasar.
Such information as there is about the host galaxies of radio-loud quasars and blazars suggests that they are also hosted by elliptical galaxies.
It has been called the naked quasar and the quasar without a home because it appears to lack a host galaxy.
