Disk Detective Talk

How to read SED properly to KNOW you're flaging a good candiate ?

  • 13lueAngeL by 13lueAngeL translator

    I would like to assure my cataloging as being accurate... and to do so, I must be pretty darn sure of what am looking at.... I checked quite a few tutorials however, not sure how to understand properly the SED data graph.

    Could someone help me ? Thanks šŸ˜‰

    Posted

  • Shigeru by Shigeru moderator

    Greetings! Both objects seems to be stars looking at the SED, but at the same time both are multiple, there are multiple objects inside the red circle and must be marked as that, not matter the SED.

    A goodcandidate would be a star but without any of the factors (I mean the options of multiple, extende, not roud, moving or empty in wise) what makes it a undesirable candidate. Don't worry to make some mistakes, I sure made my share of errors at first, but we are here also to learn! šŸ˜ƒ Here is an example of a goodcandidate (to see if is confirmed šŸ˜‰ ): http://talk.diskdetective.org/#/subjects/AWI0005np2

    So remember SED is one big clue and allow us to easy tell apart things like galaxies, quasar, AGN, but for stars the other factors are also very important.

    Posted

  • anoxie by anoxie

    That's a good question.

    When you flag an object, don't think, it's merely a visual classification designed when they have launched Disk Detective. Then, collecting the objects you can do whatever you want... most of interesting objects in my collections are not flagged as "goodcandidate" because of multiple objects in the DSS bands or because they are extended.

    Keep thinking 13lueAngeL, 2dh4 is interesting, SEDs are the funny part of the job...

    Posted

  • TED91 by TED91 moderator

    Hi @13lueAngeL,

    Here is a blog post "Examples of SEDs" in case you didn't read it yet. Maybe it helps.

    Posted

  • Shigeru by Shigeru moderator in response to TED91's comment.

    Indeed, thanks for pointing that Ted! Totally forget to link that one last night šŸ˜ƒ

    Posted

  • anoxie by anoxie

    13lueAngeL, you may have a look at the comments in the talk page and click on SIMBAD, about the 3 you've just added (you'll see a lot of these):

    -2oyr is a pulsating variable star
    -w93 is a quasar
    -23bq is extended, maybe be good spectral type, but behind a veil of interstellar medium emitting in WISE bands

    these objects are not good candidates.

    Posted

  • 13lueAngeL by 13lueAngeL translator

    Thank you all for your replies and please bare with me šŸ˜ƒ

    It was stated somewhere on this site to not necessarily discredit a subject along with what Simbad says or SED says for they are often wrong... Second but not least, in the Ted's blog post, it says that camels diagrams or not what we want yet, in this tutorial, it says to look for something like it... http://www.spitzer.caltech.edu/uploaded_files/graphics/fullscreen_graphics/0009/2675/sig05-026_Sm.jpg Am I confused ? I think I am.... all this to say, for anyone with astronomy astrophysics background, it might be quite easy to read ... just like a geneticist recognizes the bars in the genetic code... Object signatures in frequencies of light is total Chinese for most wanna-beez like moi! lollll

    The desired SED signature should be over-layered on the frame of the SED Graph so that uneducated in the matter volunteers like me have a better and quick glimpse at what it should be looking like... Now I feel I may have made dozens of mistakes and its argh! šŸ˜­(

    Ahhh! The joys of dealing with noobz šŸ˜ƒ

    Posted

  • anoxie by anoxie

    Hi,

    -When you classify the objects with DD flags you don't take into account Simbad, NED or VizieR classifications.
    You may have seen objects with a different classification according to Simbad, NED or VizieR, this can be discussed in the comment section, looking at the SED or visually at the object or at the references in Simbad may help.

    -I think "camels diagrams" are part of what we're looking for.

    -You've to interpret SEDs individually. Let's take the (nĀ°6) last one of your collection "possible good candidates" : AWI0000qp8,
    if you click on Simbad you'll see the reference "Surveying the agents of galaxy evolution in the tidally stripped, low metallicity Small Magellanic Cloud (SAGE-SMC). II. Cool evolved stars" and in VizieR you'll find the object in the catalog "Post-AGB/RGB and YSOs in SMC (Kamath+, 2014)"

    Then how can you tell based on the SED whether it is a YSO or a post-AGB star? You can't... members of the science team (abans and Luisa Rebull - see the discussion about qp8) have pointed to an annoying fact: SEDs are notoriously degenerate.

    Posted