What Produces the Arcs of Light That Appear to Be

question 275

Multiple Choice

What produces the arcs of light that appear to be centered on several clusters of galaxies,such as those shown in Figure 13-72 of Comins,Discovering the Essential Universe,6th ed.?

• A) These arcs represent the ends of plasma jets, where the material in the jets has been stopped as it ploughs into dark matter within the cluster of galaxies.
• B) These arcs represent hot gas that is being heated by friction as it orbits a supermassive black hole in the center of the cluster of galaxies.
• C) The arcs are reflections of light from the galaxies by sheets of intergalactic dust and gas, similar to the sundogs and halos around the Sun caused by ice crystal clouds.
• D) The light from a single distant source is bent by the gravitational force of both the visible material and the dark matter of the intervening cluster of galaxies.

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