Astronomical objects of all scales ranging from supermassive stars via galaxy nuclei and quasars to the universe as a whole are described on its basis.
This reference frame is based on observations of satellites and celestial radio sources known as quasars made from various co-ordinated stations around the globe.
A binary quasar, may be closely linked gravitationally and form a pair of interacting galaxies.
From counting dead quasars, he deduced that most massive galaxies have black holes at their centres.
It comprises seventy-three quasars, with a minimum diameter of 1.4 billion light-years, but over four billion light-years at its widest point.
The result is a rare example of a sixfold multiply imaged quasar.
Quasars are the furthest active galaxies, some of them being observed at distances 12 billion light years away.
It has been called the naked quasar and the quasar without a home because it appears to lack a host galaxy.
