According to current understanding,what is a quasar?
A)an active galactic nucleus that is particularly bright
B)a very large galaxy thought to be formed by the merger of several smaller galaxies,typically found in the center of a galaxy cluster
C)any object with an extremely large redshift is called a quasar
D)a galaxy with an unusually high rate of star formation

Question

Quizplus · Accepted Answer

A quasar is an active galactic nucleus (AGN) that emits a tremendous amount of energy, primarily in the form of light. It is considered particularly bright relative to other AGNs, and is powered by material falling onto a supermassive black hole at the center of the host galaxy.

Option B describes a cD galaxy, which is a very large, centrally dominant galaxy found in the center of some galaxy clusters.

Option C is not entirely correct - a redshift measurement can be used to identify a quasar, but it is not the only criterion.

Option D describes a starburst galaxy, which is a galaxy in which star formation is occurring at a very high rate.

According to Current Understanding,what Is a Quasar