Radio Galaxy Zoo Talk

Want a bigger field-of-View? Or would you like to see the corresponding optical image?

  • ivywong by ivywong scientist, admin

    As @DocR mentioned in the WISE image confusion post, sometimes there are just too many overlapping blobs in the IR images and this makes it very difficult to discern where the jets are coming from. So here are some "instruction" to access larger radio images as well as other optical images.

    1. Larger Radio images
      Using the following URL as a template example:
      http://third.ucllnl.org/cgi-bin/firstimage?RA=10.928 %2B14.540&Dec=&Equinox=J2000&ImageSize=10&MaxInt=10&GIF=1

    Divide the RA given for each of our RadioZoo images by 15 to get them into hours. Then replace the "RA=10.928" in the above URL with your RA value in hours. Then replace the "14.540" with the Dec given for each of our images.

    The "Imagesize" above has been set to 10 arcminutes and Maximum Intensity (MaxInt=10mJy). As the link works by cgi script, it'll automatically generate the needed cutout. So feel free to change these values around as you see fit. Note that our standard field-of-view is only 3 arcminutes so sometimes, parts of large nearby jets are cut off by our field-of-view.

    1. Optical counterpart images:
      (Note that not all our fields are covered by SDSS so we will have to make do with the old DSS images)
      a) To get SDSS cutouts:
      Using the following URL as a template example:
      http://cas.sdss.org/dr7/en/tools/chart/chart.asp?ra=240.16&dec=20.98&scale=0.5&width=360&height=360

    Replace the "ra" and "dec" by the RA and Dec given in each field of view. The scale above has been set to 0.5 arcseconds per pixel and so to obtain a 3 arcminute by 3arcminute image, we need to have a 360 pixel by 360 pixel image output if each pixel is set to 0.5 arcseconds.

    b)To get DSS images:
    Use the following URL as a template example:
    http://ned.ipac.caltech.edu/cgi-bin/imgdata?objname=&lon=246.3d&lat=48.22&width=3.0&height=3&search_type=DSS+Image

    Replace the "246.3" and "48.22" with the Ra & Dec given for each of our fields. The width and height are set to 3 arcminute so that can be changed to anything you like too. Note that the allowed maximum width and height is 60 by 60.

    Hope this helps

    Posted