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Polarization of quasar emissions

  1. Jul 17, 2005 #1

    turbo

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    http://xxx.lanl.gov/PS_cache/astro-ph/pdf/0507/0507274.pdf

    If quasars are at the cosmological distances suggested by their redshifts, can they conspire to be polarized similarly with respect to their line-of-sight angle to the Earth? If the universe is homogeneous and isotropic, these results cannot be real WRT to the standard model, since we cannot reside in a special place. Any thoughts?
     
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  3. Jul 17, 2005 #2

    Chronos

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    Interesting paper, thanks. I did not see anything suggesting conflict with the redshift-distance correlation or privelege wrt our sight lines. They did note an apparent 'twist' in the polarization angle that is redshift dependent and corresponds with apparent preferred directions in the CMB. From the paper:

    ... We also showed that the mean polarization angle is significantly correlated to redshift, rotating clockwise with increasing redshift in North Galactic hemisphere and counter-clockwise in the South Galactic one. Interestingly enough, the alignment effect seems to be prominent along an axis not far from preferred directions tentatively identified in Cosmic Microwave Background maps. ...

    The authors' conclusions seem reasonable, as well as intriguing:

    ... The fact that polarization vector alignments do occur on extremely large scales and seem connected on a sizeable fraction of the known Universe points towards a global mechanism acting at the scale of the Universe. While several mechanisms like global rotation may, at least partially, explain the alignment effect, we note that the observed behavior remarkly corresponds to the dichroism and birefringence predicted by photon-pseudoscalar oscillation within a magnetic field, suggesting that we might have found a signature of either dark matter or dark energy. ...
     
  4. Jul 18, 2005 #3

    Garth

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    ...or a signature of a global magnetic field?

    Garth
     
  5. Jul 18, 2005 #4

    turbo

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    Or a signature of light interacting with a local (galactic) EM field?

    "Empty" space is not empty in any sense of the word and we have no reason to assume that it cannot exhibit dynamic behavior, including polarizing effects. A uniform, empty quiescent space makes for clean calculations, but quantum field theory has some pretty compelling arguments that this is absolutely not true, especially on very small scales. If we are ever going to unify gravity with the fundamental forces, we must prepare to accept the possibility that the vacuum fields are not smooth even at large scales, but can be polarized and densified. The effects cited in this paper may turn out to have a explanation compatible with the Standard Model, but if WMAP data shows variations in the small-angle maps of the CMB between Y1 and Y2, we may be in for a fun ride, as models of macro-dynamical quantum vacua are developed.
     
  6. Jul 18, 2005 #5

    turbo

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    This is not surprising if we consider that light interacts with the vacuum fields through which it traverses. Higher-frequency EM will be more polarized, and lower frequency EM will be preferentially less polarized, since it will interact less with the medium through which it propagates.

    Optically transmissive media can more easily affect the paths and polarizations of the most energetic EM waves. It's pretty easy to design polarizing media that block high percentages of UV and blue wavelengths, making Polaroid sunglasses possible. Redder frequencies slip through more easily and are less susceptible to polarizing effects. These are practical examples from optics that have some implications for cosmology if the research in the paper is accurate.

    It may be possible to relate the polarization angles of these quasars to the redness of the sources and derive a field strength for the EM vacuum field (aether) surrounding our Milky Way and establish some frequency-related rules for interactivity of EM waves with the quantum vacuum. Graduate students should tread carefully - you are less likely to ask the King of Sweden for his meatball recipe than you are to be asking "do you want fries with that?" on the midnight shift after following this track - I have not found this to be a popular field of inquiry on this forum (the Understatement Police are beating me with nightsticks!).
     
    Last edited: Jul 18, 2005
  7. Jul 19, 2005 #6

    Chronos

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    Are you asserting the polarization angle changes at different wavelengths for the same object, or asserting a redshift-distance correlation?
     
    Last edited: Jul 19, 2005
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