Cistus, with its many hybrids and cultivars, is commonly encountered as a garden flower. The common name rockrose is applied to the species, a name also shared by the related genera Halimium, Helianthemum and Tuberaria, all in the family Cistaceae. The common name gum cistus is applied to resin-bearing species, especially C. ladanifer.
Quasars are part of a class of objects known as active galactic nuclei (AGN). Other classes include Seyfert galaxies and blazars. All three require supermassive black holes to power them.
A quasar is believed to be a supermassive black hole surrounded by an accretion disk. An accretion disk is a flat, disk-like structure of gas that rapidly spirals around a larger object, like a black hole, a new star, a white dwarf, etc.