Galaxy Zoo Talk

The hunt for Blue Caterpillars aka BBOs (Blue Blob Objects)

  • Peter_Dzwig by Peter_Dzwig

    In the tutorial at Hubble - New Images Budgieye mentioned the subject of BBOs or Blue Blob Objects - or Blue Caterpillars amid discussions on clumpy objects.

    Capella05 suggested that I post a link to the previous work we did in GZH (aka GZ3) which is online in The Forum here

    and to a Letter that I wrote up which is here http://letters.zooniverse.org/letters/56-blue_caterpillars_bbos_a_separate_class_of_irregulars_1_survey_description_and_morphology?_ga=1.230725849.711441289.1371287491 actually it's one of three Letters that I wrote up; two of which dissappeared when Letters go (at least temporarily) abandoned. There was a fourth discussing possible further investigations that should be done, but which was only the basis for a discussion with ZKChris.

    We ended up with about two hundred objects from which I compiled a list of about 70 objects for which we had a "complete" range of data including Surveys, redshifts, apparent magnitudes and absolute magnitudes etc etc. I was then able to measure the physical sizes of the main object and the blobs and count the blobs. This lead to a list of common features.

    Subsequently KWillett did a search which has yielded a load more candidates that I am working my way through.

    I set out a list of the principal features here"Blue Caterpillars - What are they? as a guide to what we were looking for. (Note that the term AHZ ID refers to the Galaxy Zoo ID and that is actually slightly different now)

    I am still looking for them so if anyone wants to join in you are more than welcome. If you find something that you think might be a Blue Caterpillar, please post it here. I am STILL trying to catalogue them.

    Note: BE AWARE that there are some odd cross-identifications in the set and a few unreliable redshifts.

    To take an older example: http://zoo3.galaxyzoo.org/examine/AHZ10003li gives a stated survey of AEGIS with a z of 1.9343. AEGIS gives a z of 0.4 for that object. Actually this DEEP2 object that corresponds to the survey number stated. NED doesn't even have a redshift for it. Just an example.

    Posted

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

    Interesting work, Peter; got my fingers crossed that it will soon result in a draft paper.

    actually it's one of three Letters that I wrote up; two of which dissappeared when Letters go (at least temporarily) abandoned.

    Are these lost forever, or do you have some sort pre-Letters draft? I'm not sure how it would go if you were to post them somewhere here - certainly the allowed formatting in the current version of Talk would likely make much of it unintelligible if simply copy/pasted.

    In the current iteration of Hubble Zoo the color mapping scheme is different from what it was in all earlier versions (at least the GOODS images/data); do you know if that will affect selection of candidate BBOs? Do you have any 'older GOODS/current GOODS' side-by-side comparisons?

    Posted

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

    I will try and rustle up some comparisons - so far I haven't been looking very hard in GZ4. I didn't think that the colours were that different. HOWEVER if they are markedly different then we need to go on other characteristics.

    Leaving aside blueness then we are looking for objects which match the criteria of shape, namely more than one ( from one to seven) grouped nuclei, showing no obvious spiral structure, often enveloped within a gas cloud, apparent mag (approx) 18 - 25. The GZ3 reference images in the link above are indicative and I will post some more here in a day or two.

    PS Yes, I do still have the pdfs and the originals. I seem to remember a discussion that you couldn't drop pdfs into Talk, nor was there a derivative of Letters available.

    Posted

  • c_cld by c_cld

    It's not clear which bandpass are used in this GZ for colorized images presented to zooites.

    For GOODS_N and GOODS_S fields, I assumed we have composites of HST ACS F435W, F606W, and F775W (BVI filters): that could mean blue color centered on pivot wavelength 435 nm for us.

    Would be different for HST WFC3 filters, or in Candels survey!

    May be the following targets fit in your collection

    http://talk.galaxyzoo.org/#/subjects/AGZ000825p GOODS full-depth GDS_N_31336 189.5004225 62.2610165 °

    GDS_N_31336 GDS_N_31336

    http://www.galaxyzoo.org/#/subjects/AGZ00084z1 GOODS full-depth GDS_S_19545 53.1528711 -27.7492434 °

    GDS_S_19545 GDS_S_19545

    Posted

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

    From Kyle Willett's post in this thread:

    For GOODS, the images are made from four bands with the Hubble filters corresponding to rest-frame B, V, I, and Z. These are combined into the color composite by using B for the red channel, a weighted mix of V and I for the blue channel, and Z for the green channel.

    Posted

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

    @JeanTate

    I've been aware of this post but I'm doubting Kyle's scheme for Goods composite: it is not in chromatic order.

    I would have preferred details on instrument (ACS or WFPC2 or WFPC3..) and its filters FxxxW (W wide or N narrow) mapped to RGB channels.

    Many images are also flipped but happily there is no question about clockwise/anticlockwise spiral arms.

    To me GZ stays opaque compared to Help/explanations from SDSS or Mast sites!

    Posted

  • Peter_Dzwig by Peter_Dzwig in response to C_cld's comment.

    Thanks for those c_cld. Yes they both qualify. GDS_S_19545 looks familiar (similar to one I have seen elsewhere, but hazier - perhaps an artefact of the new data)

    I am not sure what I think about the colour issue. I have always been told in reply to questions that the combination has been made in order to make them appear "realistic". Assuming the term to mean pretty much the same thing in all cases then I think that we should assume that if they "look blue" it will do.

    Posted

  • ramberts by ramberts

    catepillar candidate?

    Is this a candidate?

    http://www.galaxyzoo.org/#/examine/AGZ00082l3

    Posted

  • ramberts by ramberts

    Catepillar?

    Caterpillar candidate?

    http://www.galaxyzoo.org/#/examine/AGZ000851z

    Posted

  • Peter_Dzwig by Peter_Dzwig in response to ramberts's comment.

    Definitely. Thank you.Question is it one, two or three objects - or just one. If it is just one it is in. If it is a chain of galaxies it isn't. The GZH images made things a lot clearer.

    Posted

  • Peter_Dzwig by Peter_Dzwig in response to ramberts's comment.

    The previous comment was about 851z.

    8213 is much more definitely a candidate IMHO.

    Posted

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

    There seems no doubt that the new GOODS images have a non-chromatic color mapping ... for example, the formerly blue parts are now magenta/purple/violet, which means there's quite a large red-channel signal (as becomes obvious when you separate the channels). The lack of detailed info on what the transformations are is indeed unhelpful, not to mention annoying (if you're trying to do anything with the images - as data - other than do morphological classifications).

    Posted

  • vrooje by vrooje admin, scientist

    As we now have 4 filters where we once had 2, it's unsurprising that we have additional information on red colours as well as blue. Even if something that previously appeared pure blue now appears purplish, it doesn't mean there's a mistake. It means we have a more complete picture.

    Posted

  • Peter_Dzwig by Peter_Dzwig in response to vrooje's comment.

    ...but in the current batch of images we only have one. Is that true for all the current batch?

    Posted

  • Capella05 by Capella05 moderator in response to Peter Dzwig's comment.

    Hi Peter,

    The current images are part of a very small dataset (slightly less than 5000 images) - it is not expected that we will classify them for much longer (a few days at most?).

    They are galaxies from SDSS that have been previously classified by us. What is different this time around, is that we are classifying them in each of the bands seperately - the Scientiest are trying to determine if our classifications differ when we view the same galaxy in different filters.

    You can read Kyles blog post from a fortnight ago here

    Edited to add 01/06/2015: Just heard that we have about another 2 weeks to go on these images.

    Posted

  • Peter_Dzwig by Peter_Dzwig

    OK It's been a long time, but the project hasn't been wholly inactive. But it wasn't getting far. HOWEVER just this afternoon this popped up:

    enter image description here

    Point is that it ISN'T an observed object, but is an Illustris simulation object. In other words from some set of initial conditions (which I will asume are "reasonable") you can in fact get something that looks very like a BBO.

    Question is now - aprt from finding similar objects outside Illustris - has anyone found similar objects IN illustris.

    Please list them here.

    Posted

  • JeanTate by JeanTate

    Peter, do you have a hashtag for your BBOs?

    Here's one: AGZ0008d9h

    enter image description here

    Posted

  • Peter_Dzwig by Peter_Dzwig

    #IllustrisBBOs should work. Try it.

    Peter

    Posted

  • Peter_Dzwig by Peter_Dzwig

    Still looking.... 😉

    Peter

    Posted

  • harrisrej by harrisrej

    BBOs in a square formation

    Posted

  • harrisrej by harrisrej

    Other BBOs for you...

    BBO1
    BBO2
    BBO3
    BBO4
    BBO5

    Hope these are the sort of thing you're looking for.

    Posted

  • harrisrej by harrisrej

    BBO 6
    BB0 7
    BBO 8
    BBO 9
    BBO 10
    BBO 11
    BBO 12
    BBO 13
    BBO14
    BBO15
    BBO16
    BBO17
    BBO18
    BBO19
    BBO20
    BBO21
    BBO22
    BBO23

    Posted

  • zoob1172 by zoob1172

    http://www.galaxyzooforum.org/index.php?topic=277765.msg556190#msg556190 Aug. 2011 It's not entirely clear what they are but with the help of your Hubble Zoo classifications we will be able to study them better. The leading idea is that they are very gas-rich disk galaxies in the process of fragmenting. The gas turns to stars, so the individual clumps you see are clumps of intense star formation.

    Posted

  • harrisrej by harrisrej

    BBO24
    BBO25
    BBO26
    BBO27
    BBO28
    BB)29
    BBO30
    BBO31
    BBO32
    BBO33
    BBO34
    BBO35
    BBO36

    Posted

  • harrisrej by harrisrej

    BBO37
    BBO38
    BBO39
    BBO40
    BBO41
    BBO42
    BBO43
    BBO44
    BBO45
    BO46
    BBO47
    BBO48
    BBO49
    BBO50
    BBO51

    Posted

  • harrisrej by harrisrej

    Best image I've seen to date!!! Click Here

    Posted