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<< Cosmo.WebHome %TOC% ---- %INCLUDE{"BenasqueNotes2008Head"}% ---+ Dominik Schwarz - the averaging problem ArXiv:0710.5073 * compare Hubble scale and comoving distances corresponding to 180deg and 60deg as a function of z - coincidence at around z ~ 1 or so ? * BAO and SNeIa are local - SNeIa in the sense that without the z < 0.2 info the dataset loses a lot of its constraining power * WMAP alone doesn't give %$\Omega_\Lambda > 0$% * volume averaging affects power spectrum P(k) ! * !averaging time is over *time cone* volume, not comoving volume? * "synchronous coordinates" * can set %$k_D=0$% in the effective Friedmann equation * Li & Schwarz 2007: ArXiv:0710.5073 * r < 30 Mpc @z=0 %$ \Rightarrow | \frac{Q}{4\pi G <\rho>} \le \sim 0.1 $%, also %$\propto P_\xi$% * curvature corrections %$\propto \sqrt{P_\xi}$% less than 10% for r < 80 Mpc * Eq. (15) of 0710.5073 - 10% level at about 50Mpc, so above this the effects are relatively small * *Fig. 2: this inhomogeneous modelling correctly fits the growth of the variance with z in the Freedman et al 2001 H_0 set of estimates, while variance calculated for a homogeneous model underestimates the variance* * %$P_\xi$% is the "peculiar gravitational potential", i.e. initial power spectrum, it does not have the radiation-matter turn over * *idea*: this method should be used when modelling H_0 in general, for the regions below about 150 Mpc * *idea*: some work done in this direction - consider how H_0 varies in different directions and model this inhomogeneously -- Main.BoudRoukema - 29 Jul 2008
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Topic revision: r2 - 29 Jul 2008,
BoudRoukema
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