Disk Detective Talk

I Need Help!

  • jdebes by jdebes scientist, admin

    Hi everybody, and thanks so much for helping us to classify these interesting objects. But maybe you're feeling a bit lost, or need some advice? Post your questions here!

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  • mrjackoboy by mrjackoboy

    Yey! 😃

    One that may sound silly...

    Should I get excited about near perfect circular images or 'odd' shaped one?

    sorry to sound so dull, I am a complete un'scientific person, but have enjoyed helping on other zooniverse projects and really want to help with this one too 😃

    I guess if I 'tag' what I see that is all that really matters?

    Alison

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  • jdebes by jdebes scientist, admin

    I also left this comment on the image you posted--Yes, we really, really want the very round ones. We think these will be the best debris disk candidates.

    That said, we are really excited that maybe we will find some weird things that no one has seen before! So tag everything you see that looks out of place, and we'll have to use our judgement to figure things out.

    We love it that non-science people are helping out--that is the whole point! 😃

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  • mrjackoboy by mrjackoboy in response to jdebes's comment.

    I saw it, thank you , Very helpful for me 😄

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  • brainell by brainell

    Hi, awesome project. Looking forward to contributing. Two questions:

    1. It looks to me like most galaxies will appear smaller in MASS than in DSS pictures. Also on the DSS IR image they look smaller than on Blue/Red. Am I drawing the wrong conclusions or is this a useful rule? It will help with galaxies that we are seeing on axis as they may appear round. This would be a good example: http://talk.diskdetective.org/#/subjects/AWI0000asn

    2. How many pictures are there currently available for classification? The more the marrier, for me at least. 😃

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  • lrebull by lrebull scientist, translator, admin

    I'm actually not sure how many objects are in this release!

    But, as to your other question - there are at least 2 different things going on.

    The spatial resolution of the DSS and 2MASS are different. You can think of this to some extent as 2MASS having "sharper vision." So, if something was exactly the same at DSS and 2MASS wavelengths, then it might look smaller at 2MASS wavelengths. But, the "catch" here is that DSS and 2MASS are not actually at the same wavelengths, so you're actually looking at slightly different parts of the galaxy.

    Here is a page on galaxies in the infrared in general: http://coolcosmos.ipac.caltech.edu/page/galaxies
    and here is a page http://coolcosmos.ipac.caltech.edu/infrared_gallery/2
    that has a whole gallery of galaxies (thumbnails along the bottom) with sliders so that you can slide (merge) between the optical and IR views. Now, that page has Spitzer data, which is longer wavelength data than 2MASS, and moreover the galaxies that are shown there appear to us to be larger on the sky than the galaxies that have fooled us in Disk Detective. But the underlying concepts are the same - galaxies look different in the optical and IR.

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  • brainell by brainell

    Thanks for the reply.

    I know a bit about the different parts of the electromagnetic spectrum, but I don't know if galactic centres radiate more or less IR (statistically) compared to the edges. I assume they do more. In that case, my assumption that some galaxies would appear as "Not Round" in lower frequencies (visible, DSS) but appear smaller and rounder in higher frequencies (IR, MASS) might be true. Right?

    Also, I am assuming that the HH 30 YSO Disk given as an example is of many times higher resolution (by Hubble) than what DSS & MASS provided. Because of that, HH 30 images make the star appear elongated due to the dark disk in the middle, but I am expecting that on DiskDetective due to lower resolutions stars will always only appear as tiny circles, almost as dots. So because of that, out of the ~500 classifications I did so far I think about 30 to 40% have been "Not Round". Does that sound ok, or should we look for different kinds of roundness?

    For example this is "Not Round" to me : http://talk.diskdetective.org/#/subjects/AWI00000eu

    P.S.
    This is addictive!

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  • lrebull by lrebull scientist, translator, admin

    So, for the first part of your question, whether or not the center of a galaxy is bright or faint in any given band depends on what is going on near the center of the galaxy. What shape it has also depends on what is going on in that galaxy (and what angle it has with respect to us -- edge on or face on, for example). So, no, there's no hard and fast rule.

    Yes, the HH30 YSO is an edge-on disk, and it is only ("only") 140 pc=4x10^15 km away. Nearly all of the objects in Disk Detective will be a whole lot farther away than that. So, yes, HST has great resolution.. at 140 pc. Even HST won't resolve most of the sources in Disk Detective. But, yes, some of the disks you find may be edge-on. You just won't necessarily be able to tell - they will all be points to WISE (and 2MASS and DSS).

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  • lrebull by lrebull scientist, translator, admin

    Ps, yes, that "not round" one is definitely not round. Either it's a pair of stars that are comparably bright in DSS, or it's a galaxy.

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