How do we determine the distance to a quasar?
A)Quasars are all essentially identical and thus act as standard candles. We can determine the distances to the nearer ones because they contain variable stars, and the distance to a farther quasar can then be determined from its brightness.
B)Quasars contain Cepheid variables.
C)The Tully-Fisher relation is used.
D)The Hubble velocity-distance relation is used once spectroscopy gives a redshift value.

Question

Quizplus · Accepted Answer

The Hubble velocity-distance relation is used to determine the distance to a quasar once its spectroscopy provides a redshift value. This is based on the observation that the farther away a galaxy (or quasar) is, the faster it appears to be moving away from us due to the expansion of the universe. This relationship has been calibrated using various astronomical objects and can be used to estimate distances to quasars with known redshift values.

How Do We Determine the Distance to a Quasar