Galaxy Zoo Starburst Talk

List of outstanding questions

  • jules by jules moderator

    Prompted by Laura's (trouille's) comments I thought we needed a place to bring together all the questions we ask as it's becoming difficult to keep track of things. This is a start - I may well have missed some. I might even have missed other lists of questions. Please add to this thread if you find any other unanswered questions.

    Differences between v3 QS and QC catalogs and their v2 counterparts

    Where have all the..? Scroll down for mlpeck ‘s question page 2.

    Control Sample

    How to tell how much dust there is in a QS (or QC) galaxy, from the spectroscopic (or photometric) data in the catalogs?

    Beyond Background Information

    Tools: questions, issues, and comments - not sure how far the science / techie team have got with these.

    Posted

  • JeanTate by JeanTate

    Good idea, jules! 😃

    Here are some others I've noted before:

    Beyond background information - meeka777's question

    I asked the 'can you do this in Tools, if so how?' question several times. Rather than point to where, I'll simply copy/paste some sample images, with comments.

    Binning data - from either QS or QC (or both) - and plotting the means. Also, plotting data from QS against data from QC:

    enter image description here
    enter image description here

    Reversing the direction of an axis, in this case large to small:

    enter image description here

    Two different fields in one plot:

    enter image description here

    Adding lines, datasets plotted with different colors (an mlpeck chart):

    enter image description here

    A question I may have asked, vaguely: how to create, in Tools, a subset of either QS or QC which excludes 'outliers'? In this case, 'outliers' is a set of AGS Ids, possibly ~100. Of course, you can do that with a specific filter for each object you want to exclude (sorta 'uid != AGS000abcxyz'), but that gets tiresome if you have more than ~ten such.

    Posted

  • trouille by trouille scientist, moderator, admin

    As of right now, the answer is unfortunately 'no' for all of these. I'm going to email the developers with this post specifically. These are all exactly what we'd like to be able to do in Tools, but for now, have to make do without. In the Tools Facelift process (see most recent post in http://quenchtalk.galaxyzoo.org/#/boards/BGS0000006/discussions/DGS00000hf), I'll be sure to advocate for all of these. Are there other functionalities that you'd like? Please continue the thread here and we can bring all of these to the developers.

    But, for Quench, please try to do what you can within Tools. There's A LOT we can do. And there's definitely room to get even more creative for how we work within the existing constraints.

    Posted

  • trouille by trouille scientist, moderator, admin

    I've also been thinking a lot lately about Google spreadsheets and its capabilities. There's so much we could do within there and share publicly. With Quench (with only 3002 objects in the sample), it's possible to use. With larger data sets, it might not be.

    Posted

  • mlpeck by mlpeck

    Are there other functionalities that you'd like?

    A cosmological distance calculator would be nice. I have my own, but it does no-one else any good.

    Posted

  • trouille by trouille scientist, moderator, admin

    Yes, excellent idea. And I bet we could piggy back off of Ned Wrights's Online Cosmology Calculator, so the coding in the back-end may not be too tricky. In general, Ned's sites are pretty awesome.

    This makes me wonder if there are other online astronomy calculators/tools we should make the developers aware of, so they can build off of what others have already created.

    Posted

  • JeanTate by JeanTate

    Not sure if it's better to start separate threads on each of these (or add to existing ones), but here are some more questions that I have. Some have been asked before, not always directly, but they're almost certainly buried quite deeply; others are new.

    What cosmological model did you use - and what values for the parameters in it - for the x_absmag (x = u, g, r, i, z), abs_r, and luminosity_distance calculations (in the latest versions of the QS and QC catalogs)?

    How were the sfr value derived (ditto)?

    Which k-correction code did you use, and why?

    To dereden the galaxy mags, did you use the DR7 dered extinctions? If not, what was used?

    In a comment - on BPT diagrams, I think - mlpeck said that a common cut is to exclude objects/observations - H-alpha, H-beta, [OIII], and [NII] emission line fluxes, in this case - with S/N ratios smaller than 3. Is that so? Would there be any reasons why it might be better to use a different cut (in the Quench project)?

    In a project like this, what statistical tests would likely be most commonly used?

    Posted

  • JeanTate by JeanTate

    Re Tools: is there a way to show error bars (in scatterplots)?

    Posted

  • mzevin1 by mzevin1 scientist, moderator

    Tools as of now doesn't have the capabilities to show error bars, though we could just use a filter to eliminate samples with high errors as a way to eliminate galaxies with questionable data

    Posted

  • JeanTate by JeanTate in response to mzevin1's comment.

    Thanks.

    I've actually started doing just that, using Tools (nothing worth posting yet though).

    Posted

  • zutopian by zutopian

    New topic:
    Mass Dependent Merger Fraction (Control vs Post-quenched Sample)
    http://quenchtalk.galaxyzoo.org/#/boards/BGS0000008/discussions/DGS0000203?page=1&comment_id=523a07f14f6fda4b8a00020f

    Posted

  • zutopian by zutopian

    Characterising classification biases

    http://quenchtalk.galaxyzoo.org/#/boards/BGS0000001/discussions/DGS0000058

    Are the classification results already "bias corrected"? How were the results determined? Why aren't there any "uncertain" classifications?

    Posted

  • zutopian by zutopian

    Sample selection criteria and clean samples:

    I would like know, which selection criteria for spectra were used to find the Quenched galaxies? (As far I remenber, somemone asked this question in another topic before.) I doubt, that all are really quenched galaxies and I think, that some known ones were however missed.

    Topics started by Jean:

    Topic started by mlpeck:

    Posted

  • mzevin1 by mzevin1 scientist, moderator in response to zutopian's comment.

    I'm working to get the specifics of the selection criteria - I should have that info fairly soon. I will keep you posted.

    This thread talks generally on the selection criteria of the sample:
    http://quenchtalk.galaxyzoo.org/#/boards/BGS000000a/discussions/DGS00001xk

    Posted

  • zutopian by zutopian in response to mzevin1's comment.

    Thanks for your reply and for the link to the topic "Office hours", which contains general information about the selection criteria.
    I had missed and noticed now, that there is the featured science topic "Sample Selection: Post-quenched galaxy and control galaxy", which mentions the link to "Office hours". Could you please post the specifics of the selection criteria, which you are working to get and going to post soon, there.:
    Sample Selection: Post-quenched galaxy and control galaxy http://quenchtalk.galaxyzoo.org/#/boards/BGS0000001/discussions/DGS00001xy

    Posted

  • jules by jules moderator

    I think we're all in need of a little guidance now as it's becoming difficult to know what to do next. Which lines of enquiry should we follow? What should we miss out? When will we be able to access Authorea? There are some more questions - and a bit of a moan! - in this thread here. 😄 You might have to go back a page or two. There are also some more outstanding questions here too.

    Posted

  • zutopian by zutopian

    The QS sample still contains a known duplicate pair.: AGS00000j6 and AGS0000080
    One ID must be removed and the QC counterpart galaxy also.
    I mentioned this some days ago in the topic "Duplicates-Summary".:
    http://quenchtalk.galaxyzoo.org/#/boards/BGS0000008/discussions/DGS00001yd?page=2&comment_id=525b64a674983242fd0000f9

    Posted

  • jules by jules moderator

    Thought it would be easier to provide links to the most recent questions:

    (UPDATED 27 November 2013)

    JeanTate's question re sample cleaning.

    ChrisMolloy's question about age and metallicity of D4000 line. (on page 2)

    JeanTate's question re estimates of stellar mass.

    Jean Tate's questions re magnitude and fiber covering fraction

    more about fiber covering fractions

    And in relation to this: QS objects whose spectra are not nuclear

    What bias does the varying fraction of Eos - in the QS catalog - introduce?

    Posted