Galaxy Zoo Talk

QSO

  • bluemagi by bluemagi

    At 4:00 on sdss is an interesting QSO with a spectrum I haven't seen before. Could someone please explain the spectrum to me. Many Thanks BM
    Ra:206.11028 Dec:18.82525 OBJID.1237668298212835337

    Posted

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

    Is this it?

    enter image description here

    It's certainly not a carbon star! 😮

    The blue color in the SDSS image matches the spectrum ... it increases in strength from red to blue, without a break. And there are no obvious spectral lines, either emission or absorption.

    So, what is it?

    If it's a white dwarf, it's highly unusual ... WDs (should) have at least one spectral line.

    Ditto re QSO: they almost always have features, if not spectral lines.

    How about a blazar, which is where we're "looking down the barrel", i.e. one jet from the AGN is pointing straight at us? Blazar spectra are quite featureless, though I'm not sure how common it is for them to be so blue.

    Hope this helps, and happy hunting! 😃

    Posted

  • mlpeck by mlpeck

    It's a white dwarf according to Simbad, although it's listed in a QSO catalog as well. According to Wikipedia a WD with a ∼featureless spectrum is assigned a spectral class of "DC".

    A black body with a temperature ≈10000K fits the spectrum pretty well.

    Posted

  • Budgieye by Budgieye moderator

    Agree: that Object 1237668298212835337 is a white dwarf. see this link

    PAGE 3 Spectra guide for SDSS images in Galaxy Zoo Talk http://talk.galaxyzoo.org/#/boards/BGZ0000001/discussions/DGZ0000ulp?page=3&comment_id=53fef2ee3d5a77490c0001b6

    But not a blazar, which has a straight featureless spectrum.

    Posted

  • bluemagi by bluemagi

    Thanks to everyone. Was leaning to WD. Have to learn a bit more about dwarfs and qso's.

    Posted