Galaxy Zoo Talk

red core

  • GodSpewd by GodSpewd

    why some galaxys have a red core like this?


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

    Ignoring any strong line emission that there might be (and I don't know if this is significant factor for any UKIDSS galaxies), the redder the galaxy - or part of one - the stronger the long wavelength radiation detected, when compared with the shorter.

    If there were no dust, red objects would be cooler than blue ones (and in between); however, edge-on disk galaxies like this often have a lot of dust. What does dust do? It absorbs light and re-radiates it. How? By becoming warmer ... the light it absorbs is of shorter wavelength than that which it subsequently re-emits; as a first approximation you could say the stars whose light heats the dust are ~5000 to 20000K; the dust is barely 300K (and usually cooler).

    This galaxy is also interesting because - it seems to me - it has an X-shaped bulge, which is usually interpreted as a bar. Can you see it in the SDSS image? You can certainly see the dust, right?

    enter image description here

    Happy hunting!