Galaxy Zoo Talk

Discussion of: Bars as Drivers of Galactic Evolution

  • JeanTate by JeanTate

    Bars as Drivers of Galactic Evolution is a GZ blog post by newbie (blogposter) Becky Smethurst.

    Taking up Kyle Willett's suggestion - in a comment on an earlier blog post - I've started this thread/discussion in GZ Talk to, well, discuss it! 😄

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

    I'm still reading your paper, Becky, but one thing I'm already quite curious about: it seems you did not make any use of GZ Talk, is that so? If not, why not?

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  • rjsmethurst by rjsmethurst scientist

    Hi Jean,

    Do you mean you are still reading the digest of Edmund's paper that I wrote or are you reading Edmund's paper in it's entirety?

    In what way would you like to see GZ talk used?

    Becky

    Posted

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

    Hi Becky,

    Do you mean you are still reading the digest of Edmund's paper that I wrote or are you reading Edmund's paper in it's entirety?

    The latter.

    In what way would you like to see GZ talk used?

    Hmm ... well, in this thread, I'm curious to know whether you (the team) used GZ Talk at all, in the research you did (which ended up as the paper). To keep this thread focused, I'll point to a (now 3-page long) GZ Talk thread about the uses of GZ Talk! Is there a thread, here in GZ Talk, which discusses the pros and cons of Talk itself? (I posted to it earlier today, and also in the corresponding GZ forum thread).

    Back to your paper ...

    You (collectively!) write:

    We also require that for each galaxy, at least a quarter of
    all its classifications involved answering the bar question, ‘Is
    there a sign of a bar feature...’ (Masters et al. 2011). In order
    to reach the bar question, however, a user must first classify
    a galaxy as a non-edge-on galaxy with a disk or some sort of
    feature (e.g., spiral arms, rings, bars). Assuming that most
    identified features are associated with a disk, then this last selection
    effectively ensures we have non-edge-on disk galaxies.

    In the Quench project, I found that at least some of the objects classified as 'cigar-shaped' and 'in between' (down the 'smooth' arm of the decision tree) are, in fact, disk galaxies. Did your selection criteria allow for the possibility of a (de-biased) minority to vote 'bar', even though a majority voted 'smooth/in-between'?

    In order to have a volume-limited sample, we only include galaxies with Mr < -20.15, where Mr is the rest-frame absolute
    Petrosian r-band magnitude.

    (some formatting lost, sorry; Talk is not very good for anything but vanilla ASCII8 text 😦). Presumably you de-redened (sp?) for MW extinction and k-corrected, right? The same as in the GZ2DR (Willett et al. 2013)?

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