Multiple Choice
How do we know that AGNs have sizes on the order of our Solar System?
A) Quasars and Seyfert galaxies are stellar-like sources.
B) Their brightness varies by factors of a few.
C) The emission lines in their spectra show gas rotating at speeds of thousands of km/s.
D) Their brightness varies on timescales ranging from hours to a day.
E) We can measure their angular size, which gives us the physical size when we know the distance.
Correct Answer:
Verified
Correct Answer:
Verified
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