Why do I think that it isn't a lens?
by Budgieye moderator
A good question.
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.
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
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.
by Capella05 moderator
That is an amazing composite 😃
Don't you think it looks like a similar image at lower redshift in gri filters; ASW00048w0
by Budgieye moderator
Thank you c_cld, you are amazing! how you can get these images.