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New Planck mission results, Ferrara December 1-5

  1. Dec 2, 2014 #1

    marcus

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    So far a lot of the stuff from the December Ferrara conference is in French.
    Nice movie! http://videotheque.cnrs.fr/visio=4401
    Neutrino news: http://public.planck.fr/resultats/250-ce-que-planck-dit-des-neutrinos
    Latest on dark matter: http://public.planck.fr/resultats/251-planck-eclaire-la-matiere-noire-combien-quoi-ou


    The 2014 numbers are just slightly different from the March 2013 numbers (first Planck report) which we have been using:
    http://public.planck.fr/resultats/2...nck-eclaire-la-matiere-noire-combien-quoi-ou-
    ==quote==
    Combien ?
    La mesure de la densité de matière noire aujourd’hui est stable mais encore plus précise avec les résultats de la mission complète : 31.6 +/- 0.9 % de matière dont 4.92 +/- 0.03% de matière ordinaire.

    Comme on connait l’évolution de la densité de chaque type de composant (matière, rayonnement, constante cosmologique) en fonction du temps, on a la répartition des densités à différentes époques.

    ==endquote==
    They compare pie charts with WMAP and with their own planck numbers as of 2013. Only a little change from last year.
     
    Last edited: Dec 2, 2014
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  3. Dec 2, 2014 #2

    marcus

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    Notice the 31.6 mentioned above--100 minus that is 68.4,
    so we take the square root of .684 and divide today's Hubble radius by that, to get the longterm Hubble radius.
    If you say the current Hubble radius is 14.4 billion LY then paste in 14.4/(.684)^.5 and get 17.4 billion LY.
    We have been using 17.3 because last year's ".684" number was slightly higher

    I have not seen a new Planck mission estimate of the current Hubble percentage expansion rate, or equivalently the Hubble radius.
    But it looks like the basic numbers we mostly use are not changing by much.
     
    Last edited: Dec 2, 2014
  4. Dec 3, 2014 #3

    Garth

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    Thank you marcus for that link.

    And a short statement about the detection of galactic dust lanes in the area of sky examined by the BICEP2 experiment: The result is that the galactic polarization can not be neglected anywhere on the sky. The situation is far from being as clear as initially hoped the collaboration BICEP2 announcing of probably prematurely, the discovery of primordial gravitational waves in March. (Google translate)

    If you look at the dust polarisation on the map on that page you see the black box signifying the area BICEP2 looked at. Just 'above' it (towards the South Galactic Pole) is a dark blue area where there is least dust signal. Could not the BICEP2 experiment be repeated looking this time at that area?

    Garth
     
    Last edited: Dec 3, 2014
  5. Dec 26, 2014 #4

    marcus

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    More is available. For example, George Efstathiou's slides from 1 December. Cosmological model parameters.

    http://www.cosmos.esa.int/documents/387566/387653/Ferrara_Dec1_16h30_Efstathiou_Cosmology.pdf

    See for example slide #8:

    H0 estimate is either 67.3 or 67.6 depending on whether more data from other studies is included (67.6 ± 0.6 km/s per Mpc with BAO thrown in). This result is highlighted.

    The new constraints on curvature seem to narrow it down a lot! Favoring zero curvature, increasingly. (see slide #12 or thereabouts)

    Full list of available Ferrara conference slides:
    http://www.cosmos.esa.int/web/planck/ferrara2014
     
    Last edited: Dec 26, 2014
  6. Dec 27, 2014 #5

    marcus

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    I copied from George Efstathiou's table of new Planck model numbers on slide #8.
    The table heading is "Base ΛCDM Model"
    The first column is labeled "TT" and the second "TT. TE, EE"

    H0 67.3 ±1.0 --------> 67.6 ±0.6
    Ωm 0.316 ±0.014 -------> 0.316 ±0.009 (with BAO)

    the 67.6 figure corresponds to a Hubble time of "1/(67.6 km/s per Mpc)"
    Unrounded, google calculator gives Hubble radius 14.4647... billion lightyears.
    Dividing (as before in post #2) by the square root of 1 - 0.316 = 0.684 we get the longterm
    Hubble radius 14.4647/.684^.5 = 17.4897 billion lightyears.

    Efstathiou tacks on a caution that these numbers are preliminary, they won't publish until sometime next year. But still it looks like when we round off the longterm Hubble radius is going to say 17.5 billion LY.

    In Jorrie's outstandingly useful Lightcone calculator the Hubble radii used so far, based on the Planck 2013 numbers, have been 14.4 and 17.3 billion LY. It looks like sometime in early 2015, when Planck data is published, they might have to change, perhaps to 14.5 and 17.5. But that is just a guess.
     
    Last edited: Dec 27, 2014
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