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Cold spot in CMB

  1. Nov 3, 2015 #1

    wolram

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    Is this a systemic error?
    Quote from wiki
    The cold spot is mainly anomalous because it stands out compared to the relatively hot ring around it; it is not unusual if one only considers the size and coldness of the spot itself.[7] More technically, its detection and significance depends on using a compensated filter like a Mexican hat wavelet to find it.
    end quote.
    Or is it real?
     
  2. jcsd
  3. Nov 5, 2015 #2

    bapowell

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    The latest Planck analysis concludes that it's anomalous: http://arxiv.org/pdf/1303.5083v3.pdf (see section 5.9), which means that people are looking for a cosmological explanation for it.
     
  4. Nov 5, 2015 #3

    wolram

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    Hmm, thanks bapowell, from the paper:

    . Attempts to explain the observed features in terms of systematic artefacts, local astrophysical sources of emission, or structure in the local Universe have not been successful. It is clear that these anomalies represent real features of the CMB sky.

    IS the LCDM in danger?
     
  5. Nov 5, 2015 #4

    bapowell

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    Together with the other CMB anomalies, it certainly compels a raised eyebrow. The difficulty with assigning significance to these anomalies is that even Gaussian random fields will have features that appear non-Gaussian from time to time.
     
  6. Nov 5, 2015 #5

    wolram

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    Thank you bapowell.
    I have come across this paper: Cosmology with Coupled Gravity and Dark Energy

    http://arxiv.org/pdf/1409.0782.pdf

    It seems to me that it explains these anomalies and deals well with other problems::

    Dark energy is a fundamental constituent of our universe, its status in the cosmological field equation should be equivalent to that of matter gravity. Here we construct a dark energy and matter gravity coupling (DEMC) model of cosmology in a way that dark energy and matter are introduced into the cosmological field equation in parallel with each other from the beginning. The DEMC universe possesses a composite symmetry from global Galileo invariance and local Lorentz invariance. The observed evolution of the universe expansion rate at redshift z > 1 is in tension with the standard LCDM model, but can be well predicted by the DEMC model from measurements of only nearby epochs. The so far most precise measured expansion rate at high z is quite a bit slower than the expectations from LCDM, but remarkably consistent with that from DEMC. It is hoped that the DEMC scenario can also help to solve other existing challenges to cosmology: large scale anomalies in CMB maps and large structures up to ∼ 103 Mpc of a quasar group. The DEMC universe is a well defined mechanical system. From measurements we can quantitatively evaluate its total rest energy, present absolute radius and expanding speed.
     
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