Galaxy Zoo Talk

"Twin peaks" MgII emission in quasars?

  • JeanTate by JeanTate

    I have come across two QSOs which have what seems to me to be a strange structure in their (rest frame) 279.9 nm MgII lines: zsp 1.738 SDSS J102459.80+062453.7 (top), and zsp 0.978 SDSS J150824.72+560423.3 (bottom).

    In both cases, the line seems to have two (broad) emission peaks and a (narrow) absorption feature in between. To me, this would normally suggest an emission source that is either rapidly rotating or expanding (or extremely hot, but if so, there'd be no singly-ionized Mg!), with a cold cloud of ~stationary (from our perspective) material in the foreground. Oh, and no other line seems to have this "twin peak" feature ...

    Does anyone reading this know what these MgII features are? And how common are they in QSOs?

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    Posted

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

    This seems helpful (just glanced over it yet):

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    http://astronomy.nmsu.edu/cwc/Research/MgIIreview/mgii-over.html

    Posted

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

    Thanks.

    The use of MgII absorption lines, with a background quasar proving the illumination source, is very cool! 😃

    However, these lines arise from interstellar (and intergalactic) stuff that's far in the foreground of the quasar; the two QSO spectra I posted have MgII features that surely arise in, or close to, the galaxy which has the QSO as its nucleus.

    Posted

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

    Ah yes ofcourse the restframe of 279.9 nm. I looked for foreground galaxies in the vicinity but couldn’t spot them.

    Hmm should be ‘fairly’ easy to calcute the redshift of the absorption lines to see if they match with the QSO’s z’s? ( unable right now)

    EDIT: woops you probably already checked that, yes they (mgII 2799 features) seem to have the ~same z as the QSO’s. Hmm

    Posted

  • JeanTate by JeanTate

    Here are some examples of QSOs (actually quasars, they are all prominent radio sources) with prominent, broad MgII in emission ... without a narrow absorption line in the middle:

    SDSS J123157.08+542028.6:

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    SDSS J154232.02+493842.6:

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    SDSS J084312.42+612943.8:

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    SDSS J135927.15+015954.6 (this does have a small abs feature):

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    SDSS J164258.26+125109.3:

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    SDSS J164931.83+262323.6:

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    Posted