Galaxy Zoo Talk

Overlappng or merging?

  • suelaine by suelaine

    Are these almost identical ellipses merging or overlapping? I believe that the bright object below the bottom galaxy is a star. If there was an overlap then in a few million years there might be an eclipse.

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

    Yes, the bright white object - which is, in fact in the center (and which the SDSS photometric pipeline thinks is a galaxy!), and so is what we're supposed to classify - is a star.

    The two yellowish galaxies are 'ETGs', 'early-type galaxies', informally called 'ellipticals'. As ETGs are, for the most part, devoid of gas and dust, and as they often do not have disks, it's much harder to tell - just from eyeballing them - whether two like this are merging or simply overlapping ... no obvious distortions, no 'tidal tails', no weird dust lanes ... I think it might be possible to tell if they're merging or overlapping if they were observed with a super-advanced instrument on a big telescope, but until then ...

    Posted

  • suelaine by suelaine

    Thanks Jean Tate….. suelaine

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

    You're welcome suelaine.

    Yes, the bright white object - which is, in fact in the center (and which the SDSS photometric pipeline thinks is a galaxy!), and so is what we're supposed to classify - is a star.

    Actually, as an eagle-eyed zooite pointed out to me (via a PM), what's in the center (in this case) is the middle yellow blob - an ETG! 😦 (thank you, my fellow zooite).

    The white star was served up to be classified, but it's AGZ0003lig (discussion on it here), not AGZ0003lie. Will likely be a real headache for the Science Team to merge the classifications!

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  • suelaine by suelaine

    OK,if the bright white object at the bottom is a galaxy, then is it an AGN?

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

    But it isn't; it's an ordinary star, in our own galaxy (the automatic SDSS photometric pipeline made a mistake).

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