Radio Galaxy Zoo Talk

Do detached 'head-tail' radio structures exist?

  • JeanTate by JeanTate

    Here's what triggered this question (it's in the ARG00035wv - cluster core has either very extended BCG or a LOT of ICL/IGL! thread):

    enter image description here

    If the ultimate source of the radio emission is the giant elliptical in the center of the image, how unusual is such a detached, one-sided structure?

    I re-read the GZ blog posts on RGZ, especially the two by Heinz Andernach (here and here), paying particular attention to hints of congifurations like this. Certainly, there were/are plenty of 'tadpole-like' radio structures ... but they all seem to have the host at/near either end, not detached (a really nice compilation is An Atlas of DRAGNs). Further, in Classification Schemes for DRAGNs, there seemed to me to be no class into which this sort of detached head-tail would fit.

    Anyone?

    Posted

  • 42jkb by 42jkb scientist, admin in response to JeanTate's comment.

    Yes you can observe detached one-sided radio structure. The other lobe may be very diffuse and not pick up in FIRST, so looking at NVSS or another radio wavelength you may be able to observe the other lobe. Another effect can be the Laing-Garrington effect or Doppler boosting.

    However, for this source and the alignment of the radio emission with respect to the elliptcial galaxy I would say that they may not be related and that the host galaxy to the radio emission is too faint for SDSS and lies in the centre of the radio emission.

    Posted

  • JeanTate by JeanTate in response to 42jkb's comment.

    Thanks! 😃

    The only thing which shows in NVSS is the same source as FIRST; no second lobe.

    Doppler boosting is (largely) a perspective effect, isn't it? If the jets have a low angle of inclination, with respect to our sightline, the jet coming towards us will be Doppler boosted compared with the one going away from us.

    Does this apply to lobes as well? I mean, aren't lobes (mostly) where the jets stop, so much less Doppler boosting.

    Posted

  • JeanTate by JeanTate in response to 42jkb's comment.

    Would this be an example of Doppler boosting*?

    enter image description here

    There does seem to be two jets, with the one on the N much stronger than the S one.

    *Discussion here

    Posted

  • 42jkb by 42jkb scientist, admin in response to JeanTate's comment.

    Yes, doppler boosting usually occurs in the jets. The lobes is more of a laing-garrington effect and relativistic beaming.

    As for your example, this looks like a relativistic beaming effect. Not too sure why I even mentioned doppler boosting in the first place :S

    Posted

  • JeanTate by JeanTate in response to 42jkb's comment.

    As for your example, this looks like a relativistic beaming effect.

    Cool! 😃

    How do radio astronomers go about ascertaining if we are, in fact, seeing relativistic beaming?

    Posted