How Do X- Ray Measurements Help Us Measure the Amount

question 102

Multiple Choice

How do X- ray measurements help us measure the amount of dark matter in galaxy clusters?

• A)X- rays are emitted by hot gas, and the intracluster gas is heated by collisions with dark matter particles. More dark matter leads to greater heating, and hence stronger X- ray emission.
• B)X- rays are emitted by hot gas, and the intracluster gas is heated by the gravitational effects of dark matter. More dark matter leads to greater heating, and hence stronger X- ray emission.
• C)Dark matter absorbs X- rays. Therefore, more dark matter leads to weaker X- ray emission from galaxy clusters.

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