Why is the energy source for active nuclei like Seyferts thought to be compact?
A)The sources appear to be single stars in photos.
B)Their energy appears to be non-stellar synchrotron radiation.
C)The light can vary over short time intervals.
D)We know the masses of the black holes that lurk there, and can find their radii.
E)They are all strong radio sources, with assigned frequencies by their sizes.

Question

Quizplus · Accepted Answer

The fact that Seyfert nuclei have variable light over short time intervals suggests that their energy source must be compact, since only small objects can change their brightness so rapidly. The fact that the light from active nuclei like Seyferts can vary over short time intervals is an indication that their energy source is compact. This rules out options A, B, D, and E, since they do not provide an explanation for the compactness of the energy source.

Why Is the Energy Source for Active Nuclei Like Seyferts