Space Warps Talk

Why do I think that it isn't a lens?

  • Budgieye by Budgieye moderator

    A good question.

    enter image description here

    http://talk.spacewarps.org/#/subjects/ASW0001zpw

    I don't have access to any data or dashboard, so I must reply on what I see and past experience.

    Shape: to me, I can see some lines and blobs in the blue, and possibly see the attachment to the nucleus. An arc looks like a smooth blue shape that doesn't belong.

    Colour: to me, light blue at the distance to this galaxy, which to me looks about z=0.1, means star-forming. The blue colour is made by lots of blue stars plus other colours of stars, which when mixed together makes white blue.

    A lensed galaxy can also be blue and star-forming, but is far away at z= 1.0 , and the blue star colour has been redshifted to red. But there is a blue colour which comes into the visual spectrum due redshifting of ultraviolet light. So red + blue= blue with a bit of red = reddish blue = purple (actually magenta) a dark colour.

    EDIT (as I thought of more things): very distant galaxies z=2) lose the red light, and the arc shines very bright white blue. But there will be no detail in the arc.

    If I lens is buried in the lensing galaxy, it's colour will change.

    http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=588290880028999911

    ASW0001zpw (above), I thought was star-forming but I may be wrong.

    ASW0002hxu (below) is a strange colour and shape, so I put it on my list. The "arcs" possibly have a hint of purple, though not very convincing. The scientist can easily ignore it.

    Perhaps a scientist thinks that I should include this and others like this on my Collect list, just to be on the safe side. Then I will include more like this.

    Please look at these links. The colours of the SDSS survery are much like CFHT so the same principles apply.

    http://www.galaxyzooforum.org/index.php?topic=277142.0 Colours of Galaxies in SDSS : Redshift chart

    http://www.galaxyzooforum.org/index.php?topic=274815.0 Zooite Guide to SDSS Spectra

    enter image description here

    http://talk.spacewarps.org/#/subjects/ASW0002hxu

    Posted

  • c_cld by c_cld

    When looking at ASW0001zpw, I saw two pink dots at the tips of the withish ovoid: for me it's a hint of ends of a bar .

    I went to the filters fits files and did some image processing. I posted in GZ my result with a copy here.
    ASW0001zpw

    Hope you will be convinced of a #no_lens for this one ASW0001zpw!

    Posted

  • Capella05 by Capella05 moderator

    Thanks Claude!

    That is an amazing composite 😃

    Posted

  • c_cld by c_cld

    Don't you think it looks like a similar image at lower redshift in gri filters; ASW00048w0

    ASW00048w0

    Posted

  • Budgieye by Budgieye moderator

    Thank you c_cld, you are amazing! how you can get these images.

    Posted