Radio Galaxy Zoo Talk

An interesting one to me!

  • rtconr by rtconr

    pretty awesome symmetry in this one!


  • DocR by DocR scientist

    Glad you liked it, but it's a little misleading. The two identical sets of contours mean that there are two structures each of which is quite small. So what you're looking at is the pair of radio "beams", just an indicator that there's something at that position, but no details visible. So all the interesting structure is probably hidden.


  • Tobend by Tobend in response to DocR's comment.

    Thanks for all your useful comments on the site DocR but I find the use of the word beams a bit confusing.

    I assume you mean beams from the (separate ) radio structures and not the effective beam size, i.e. point spread function (PSF), of the telescope?

    That the shape of the image implies the presence of two structures but the almost identical contours suggest that they may be at the limits of resolution and dominated by the PSF?

    I have been tagging sources similar to this one as hourglass whenever the brightest regions are separated by more than, approximately, half the size of the entire radio source, in accordance with the definition in 'suggested hashtags'. I have done this on the basis that the tags are intended, primarily, as a functional description of the image though RGZ also relies on judgements about the nature of the radio source. Have I been using the tag too enthusiastically?

    Finally I wonder whether displaying a 'ruler' indicating the FWHM of the PSF, or something similar, on the RGZ images might be a useful addition?


  • DocR by DocR scientist

    Sorry for the confusion. I did mean the PSF, effective beam size of the telescope -- yes, they are resolution limited and dominated by PSF. That's what the contours are showing in FIRST - so it looks like two unresolved sources.

    You're probably a bit liberal on the #hourglass classification, but no harm done. What that will indicate to us is that you think the components are part of one source, and that's the most valuable thing.

    I'll talk to the science team about a PSF display, but in general, the philosophy has been to keep things as uncluttered as possible. Now that you know what the PSF looks like, it will be the same on all images that come from FIRST. That will change later on when we bring in other surveys, so the question will get more serious. Thanks for the ideas.