Radio Galaxy Zoo Talk

ARG0000z9e NO OBJECTS FOUND EVERYWHERE & REAL STARS.

  • 1001G by 1001G

    SDSS J171648.37+431451.1 .
    OTHER STARS SDSS J171647.78+431538.1 & SDSS J171647.03+431550.3.
    RADIO SOURCE IS A NO OBJECT FOUND.

    enter image description here

    REAL STARS & NO OBJECTS FOUND.

    Posted

  • ivywong by ivywong scientist, admin

    There is certainly a lot of foreground stellar contamination and so the likely host galaxy for this radio source would be a background galaxy that is not seen in these images.

    Posted

  • 1001G by 1001G

    SPECTACULAR NO OBJECTS FOUND AREA & STAR AREA. IT EXTENDS FAR SOUTH & FAR NORTH.

    enter image description here

    Posted

  • akapinska by akapinska scientist in response to 1001G's comment.

    Oh, this is interesting!

    So what you are really looking here at is a star cluster. I found it is M92 cluster (Messier object), and it has been suggested to be a dwarf galaxy orbiting our Milky Way http://adsabs.harvard.edu/cgi-bin/bib_query?2008A%26A...477..139L

    I zoomed out a bit in SDSS and that is how it looks like in its full glory (SDSS10; the marked position is where our radio source is):

    enter image description here

    Quite a beauty, isn't it? 😃

    But the radio emission you got to classify in RGZ is most likely not related, that is there is probably a background radio galaxy (actually two), have a look at these FIRST contours overlaid on RGB SDSS10 image:

    enter image description here

    Of course, there is a separate question of why SDSS doesn't have catalogued any sources around this field, and I would think that maybe this is because the field is too crowded. Well, that's just my guess. We could try to do the photometry ourselves by hand to get any information on the host galaxies of this radio sources.

    Posted

  • 1001G by 1001G

    RADIO SOURCE STAR? GALAXY?

    enter image description here

    enter image description here

    Posted

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

    Here's my contour overlay image:

    enter image description here
    enter image description here

    I agree that the two hosts are background galaxies, both likely giant ellipticals.

    Of course, there is a separate question of why SDSS doesn't have catalogued any sources around this field,

    Some time after DR7, SDSS made a change to where it identifies photometric objects, in 'large' regions with high surface density - such near big bright galaxies like M87, or globular clusters; they realized that the photometric pipeline gave unreliable estimates, so they 'masked out' these parts of the sky. I wrote about this in this GZ forum thread (and got a couple of SDSS scientists to chime in) There's a hole in the sky (several actually).

    The image in this post was created from sources, and using methods, described in this RGZ Talk post. The position of the center of the image is (143.8539, 23.9178).

    Posted