Suppose We Observe a Source of X-Rays That Varies Substantially

question 1

Multiple Choice

Suppose we observe a source of X-rays that varies substantially in brightness over a period of a few days.What can we conclude?

• A)The X-ray source is a quasar.
• B)The X-ray source contains a black hole with an accretion disk.
• C)The X-ray source is no more than a few light-days in diameter.
• D)The X-ray source must have a strong,rapidly varying magnetic field.
• E)We are seeing the rapid orbit of two stars in a binary system.

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