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Detecting a Galaxy Cluster With a Radio Telescope

-- | November 24, 2013

Question: Is it possible for a 7-m radio telescope to detect a galaxy cluster of redshift below 0.03? — Ungku

Answer: Yes, as long as the cluster is big and bright enough at the radio frequency at which you want to detect the cluster. The sensitivity of a radio telescope is proportional to the noise temperature of your detector system divided by the product of the effective area of your antenna, the square root of the bandwidth of your detector system, and the square root of the amount of time that you integrate on the source of interest. Since the effective area of your antenna contains a term which is proportional to the area of the source in your antenna resolution element, you can see that as the size of the source gets bigger the sensitivity of your measurement improves. Your measurement sensitivity also improves if your system noise is lower, and if your integration time and bandwidth of your detector system is larger.

Jeff Mangum

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