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Definition of the antenna temperature |
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| | Let us assume now that our telescope observes over a limited frequency range, |
, (the so-called "passband") with constant response over that range. When pointing at a blank portion of the sky, there are only contributions from what one would call "background" or "noise". The power of this component can be expressed as б
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| | Similarly, the power of an astronomical source can be expressed as |
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| | where |
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is the so-called "antenna temperature", which is a measure of the temperature equivalent of the power received from an astronomical source. ASKAP
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