Evidence for anisotropy of cosmic acceleration Subir Sarkar Colin, Mohayaee, Rameez & S.S., A&A 631: L13, 2019 Rudolf Peierls Centre for Theoretical Physics 2019 1929 2016 2001 Seminar , U , Universi sity o y of G Geneva, 1 , 17 D December 20 2019
All we can ever learn about the universe is contained within our past light cone We cannot move over cosmological distances and check if the universe looks the same from ‘over there’ as it does from here … so there are limits to what we can know (cosmic variance)
<latexit sha1_base64="51ZpQU/7JoM1nBLtKyfzpNYhoVQ=">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</latexit><latexit sha1_base64="AdU/Mra5g13ogMW+ETWlZL5ZXyo=">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</latexit><latexit sha1_base64="AdU/Mra5g13ogMW+ETWlZL5ZXyo=">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</latexit><latexit sha1_base64="RqT+kXNr6jO9+ym5MT2+WvKA=">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</latexit> Standard cosmological model The universe is is isotr tropic ic + ho homogene neous us (when averaged on ‘large’ scales) ⇒ Maximally-symmetric space-time + id ideal l flu fluid id energy-momentum tensor ds 2 ≡ g µ ν dx µ dx ν R µ ν − 1 2 Rg µ ν + λ g µ ν = a 2 ( η ) d η 2 − d ¯ x 2 ⇤ ⇥ Einstein = 8 π G N T µ ν T µ ν = �h ρ i fields g µ ν Robertson-Walker a = − 4 π G ¨ ( ρ + 3 P ) a. 3 k Λ ρ m Ω m ≡ 0 / 8 π G N ) , Ω k ≡ 0 ) , Ω Λ ≡ (3 H 2 (3 H 2 0 a 2 (3 H 2 0 cosmic sum rule ’: W m + W k + W L = = 1 So the Fr Friedmann-Le Lemaitre equation ⇒ ‘ co CMB ), W m ~ 0.3 ( Cl We observe: 0.8Ω m - 0.6Ω L ≈ -0.2 ( Su Supernovae ), Ω k ≈ 0.0 ( CM Clusters ) nergy : W Λ = 1 - W m - W k ~ 0.7 ⇒ Λ ~ 2 H 02 ➙ infer universe is dominated by da dark ene The scale is set by the only dimensionful parameter: H 0 ~ 10 -42 GeV gative ( P < - r /3) so this is To drive accelerated expansion requires the pressure to be ne negat interpreted as vacuum energy at the scale ( r L ) 1/4 = ( H 02 /8 p G N ) 1/4 ~ 10 -12 GeV << G F-1/2 ~ 10 2 GeV This makes no physical sense … exacerbates the (old) Cosmological Constant problem!
W L ≡ L /3 H 02 r L ≃ H 02 M P 2 ~ (10 -12 GeV) 4 There has been substantial investment in major satellites and telescopes to measure the parameters of the ‘standard cosmological model’ with increasing ‘precision’… but surprisingly little work on testing its foundational assumptions
The Universe must appear to be the same to all observers wherever they are This ‘ co cosmological principle ’ … Edward Arthur Milne (1896-1950) Rouse Ball Professor of Mathematics & Fellow of Wadham College, Oxford, 1928-
“Data from the Planck satellite show the universe to be highly isotropic” (Wikipedia) We observe a ~ statistically isotropic ~ Gaussian random field of small temperature fluctuations (quantified by the 2-point correlations ➛ angular power spectrum)
But the CMB sky is in fact quite anisotropic There is a ~ 100 times bigger anisotropy in the form of a dipole with D T / T ~ 10 -3 Stewart & Sciama 1967, Peebles & Wilkinson 1968 p 1 − β 2 T ( θ ) = T 0 1 − β cos θ This is interpreted as due to our motion at 370 km/s wrt the frame in which the CMB is truly isotropic ⇒ motion of the Local Group at 620 km/s towards l =271.9 o , b =29.6 o This motion is presumed to be due to local inhomogeneity in the matter distribution Its scale – beyond which we converge to the CMB frame – is supposedly of O (100) Mpc (Counts of galaxies in the SDSS & WiggleZ surveys are said to scale as r 3 on larger scales)
Scrimgeour et al , MNRAS 425 :116,2012 However the biggest spheres are not fully contained in the WiggleZ survey volume … so were filled with galaxies drawn from a ΛCDM model simulation!
This is what our universe actually looks like locally (out to ~ 300 Mpc) We are moving towards the Shapley supercluster supposedly due to a ‘Great Attractor’ Courtesey: Richard Powell 100 Mpc If so, our ‘peculiar velocity’ should fall off as ~1/ r so we “converge to the CMB frame”
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