How Do We Measure Directly That AGNs Have Black Holes

question 41

Multiple Choice

How do we measure directly that AGNs have black holes at their centers?

• A) We know that massive stars make black holes, and most galaxies contain a lot of massive stars.
• B) We know black holes are made of dark matter, and galaxies are mostly made up of dark matter.
• C) We know that black holes emit radio waves, and many AGNs are bright at radio waves.
• D) We measure that the mass of the black hole is increasing as material falls into it.
• E) In some systems, we can see both redshifted and blueshifted emission lines from material orbiting around the black hole.

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A person who is under the legal age of majority, and therefore has limited legal rights and responsibilities.

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