Radio Galaxy Zoo Talk

Is this a well-known kind of source?

  • JeanTate by JeanTate

    In some ways it resembles a double lobe, but it doesn't have a 'waist'. It does, however, have a (faint) IR source near its center.

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  • ivywong by ivywong scientist, admin

    I would actually call this a #compact source. Perhaps we may see a more defined "waist" if we had higher angular resolution in the radio image but difficult to say with this image. Hope this helps 😃

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  • JeanTate by JeanTate in response to ivywong's comment.

    Yes it does, thanks.

    So much larger - as measured by angular size - elongated/elliptically-shaped radio sources, with a central IR source, without a 'waist' would be unusual?

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  • ivywong by ivywong scientist, admin

    It could be a jet shooting out both ways + a peak for the core. In this case, the "triple" looking jet won't have much of a 'waist'. Apart from the exotic and unusual looking jets that many Citizen Scientists are starting to find, radio astronomers have 2 main classes of radio jets. FR I and FR II. Check out this link for a quick explanation: http://www.cv.nrao.edu/~abridle/bgctalk/node4.html

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  • JeanTate by JeanTate in response to ivywong's comment.

    Thanks! 😄

    Yes, I see that a triple could easily look like a smooth, elliptically-shaped source. Even higher resolution would show - hopefully - that it had two 'waists'.

    [...] radio astronomers have 2 main classes of radio jets. FR I and FR II.

    Hmm, I'm not sure I can readily match these to what we've (well, I've) been finding: it seems that both FR I and FR II sources could look like doublelobes (depends on resolution, and the strength - or not - of the central source). Maybe I should start a thread on these (I can't be the only zooite to have wondered)?

    Also, it says polarization is very helpful, as a diagnostic; does the ATLAS observational data include polarizations?

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  • ivywong by ivywong scientist, admin

    These 2 main classes only provide rough guides. As you know from working on Radio Zoo that there are lots of objects that don't fit neatly into these 2 categories. The way I think of them generally is whether there are hot spots (FRII) or if the emission appears fairly "continuous"/linear (FRI). There are even sources (hybrids) where one side of the jet is FRI while the other side has more of an FRII morphology.

    It's not particularly useful for us to try to classify our current sample into FRI or FRII for the exact reasons that you outlined. How the jets look can depend on resolution, sensitivity as well as line-of-sight to the jet. By sending you to the link above, I was trying to give you an idea of how nicely-resolved jets could look like. Since most of our sources do not have sufficient resolution, I wouldn't worry too much trying to class these objects into FRI or FRII. On the other hand, if you think that it'd be useful for the Zooites to also see what nicely-resolved jets look like, feel free to start a thread 😃

    Polarization is helpful but we won't be including them in Radio Zoo (not yet at least) .. We do have polarisation data for ATLAS. Perhaps @enno.middelberg or @42jkb can comment more on these....

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