2 lobes or 2 emission centres?
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by
turelli
do the curves in the diagrams represent iso-frequency lines?
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by
JeanTate
in response to turelli's comment.
Welcome to RGZ, turelli!
If you mean the contour lines - like on a topographic map - then no. The lines are equal intensity, or radio-strength, a bit like height, or altitude on a topographic map.
More specifically, the lowest contour lines are set at ~three times the "sigma" of the "noise", and each one is sqrt(2) greater than its lower neighbor. Instead of metres, the lines are (some fraction of) Janskys (Jy), which is a unit of something called "flux". Flux is energy per second per square meter per unit of frequency (yeah, it's a bit complicated; holler if you'd like me to explain in more detail). Noise is just that, the random noise that the radio telescope detectors pick up (it's actually not random, but that's a whole other story!). Sigma is - if you're familiar with it - one standard deviation, and the lowest contour is set so that only rarely will noise be flagged as a real radio source.
Hope this helps, and happy hunting! 😃
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