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.
3C 273 is a quasar located in the constellation Virgo. It was the first quasar ever to be identified. It is the optically brightest quasar in our sky (m ~12.9), and one of the closest with a redshift, z, of 0.158.A luminosity distance of D L = 749 megaparsecs (2.4 Gly) may be calculated from z.t is the optically brightest quasar in our sky (m ~12.9), and one of the closest with a redshift, z, of 0.158. A luminosity distance of D L = 749 megaparsecs (2.4 Gly) may be calculated from z.