pink galaxy
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by
suelaine
galaxy pink throughout. I see that on SkyServer that it is an orange colour. It must have something to do with the telescope and wavelength.
Posted
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suelaine
What makes this galaxy pink throughout?
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JeanTate
in response to suelaine's comment.
Great question!
Not sure in general, but this particular galaxy appears pink only in the bulge (to me, anyway; I should really check it out in more detail ... perhaps later).
I've seen quite a few 'pinkish bulge' galaxies, at least somewhat like this. Often - but not always - they're Eos ('edge-on spirals'; that's my own term, not something you'll find in an astronomy textbook!). And the UKIDSS pink corresponds to yellow/orange in SDSS. My interpretation of these (not pink-in-general, just the Eos's): we're seeing the bulge through a very great amount of dust. Dust 'reddens'; it preferentially scatters/absorbs blue light ('blue' here is relative; shorthand for 'shorter wavelength'). Warm dust also emits light, especially in the mid-IR, which - very roughly - is partly covered by the UKIDSS filter mapped to R (red) in the RGB JPG images we get to classify. So the combined effect of lots of dust is to:
- make Eos bulges look orange in SDSS images
- make them look pink in UKIDSS images
But why not 'red' (instead of 'orange') or 'red' (instead of 'pink')? Because the dust screen is not so thick that it blocks all the shorter wavelength light.
Hope this helps. And please keep asking good questions like this! 😃
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JeanTate
I just had a similar one to classify, AGZ0006k6p:
Not quite the same shade of pink, but still ...
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suelaine
Yes, thanks
suelainePosted