Radio Galaxy Zoo Talk

Why do so many radio sources seem to be within diagonal artifacts?

  • JeanTate by JeanTate

    ARG0002r8f is just one example:

    enter image description here

    The radio sources - two in the case - are almost entirely within the ~15" (?) wide band of enhanced background, the one slanting from NE to SW (they're also both within horizontal bands, but not as pronounced).

    The triangular shape of the background is due to the way the images are created, right? It's a result of the particular configuration of the radio interferometer (I think).

    Could it be that the location of radio sources at intersections of enhanced background is not a bug but a feature?


  • DocR by DocR scientist

    There are two related issues at work here. Yes, it is the interferometer that is putting some of the signal power into these diagonal stripes. If you look at the initial map as it comes off the telescope, these are much stronger, and we work to get them down as far as we can. The next thing is that since the noise is higher along the stripe, a faint source that would not be seen elsewhere in the image but become visible if it's coincident with a region of higher noise. So faint things are also found along the diagonal stripes created by nearby sources. it's something that has to be carefully calibrated when people are doing counting statistics, spatial corrlations, etc.

    I wouldn't classify it as a feature 😉, but it would nice if it were.