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CMB lensing and cosmic acceleration

CMB lensing and cosmic acceleration. Viviana Acquaviva SISSA, Trieste. Outline. Physics of lensing From CMB to dark energy Results and forecasts. lens plane. unlensed image. source. α. lensed image. deflection angle. lens. geodesic equation. Einstein equations.

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CMB lensing and cosmic acceleration

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  1. CMB lensingand cosmic acceleration Viviana Acquaviva SISSA, Trieste

  2. Outline • Physics of lensing • From CMB to dark energy • Results and forecasts

  3. lens plane unlensed image source α lensed image deflection angle lens geodesic equation Einstein equations small deflection angles  WEAK LENSING

  4. lensing selection effect CMB light from LSS DE OVERLAPPING  z 1000 ~ 1 0 why lensing for dark energy? us r/H0-1 ~ 2 ~ 1 0

  5. source emission observed image lensing is quadratic in the cosmological perturbations ! lensing generates UNBIASED B-modes at l > 100 ! there is a CMB observation in the DE-related redshift window hard life if we are dominated by primary anisotropies CMB lensing phenomenology re-mapping

  6. - - unlensed • lensed Temperature power spectrum

  7. B polarization modes power spectrum reionization primordial GW lensing

  8. B polarization modes power spectrum unbiased observable, tracking DE at lensing epoch

  9. plan of our work • Formal extension of lensing framework • to generalized theories of gravity VA, Baccigalupi and Perrotta 2004 2. Study of lensed B signal in different models RP: V() = M4+/ (aka IPL) Ratra & Peebles 2000 SUGRA: V() = M4+/ e4(/Mpl)2 Brax & Martin 2000 VA & Baccigalupi 2005

  10. evolution of gravitational potential background expansion W = (χLS – χ)/χLS Ψ generalized gauge-invariant variable accounting for all the fluctuating components Pψ(k,χ) ≠ T2(k,0) g2(χ) lensing of the spectra performed in the main integration routine (all k,z needed!) no analytical fit is available technicalities  lensed correlation functions are obtained by a convolution with a gaussian of arguments: Zaldarriaga & Seljak 1998

  11. SUGRA IPL SUGRA IPL RESULTS FOR THE QUINTESSENCE MODELS no anisotropic stress basically geometry effects tracking behaviour  main dependence is on α w0 = - 0.9 tuned to get Geff = G0 SAME PRIMORDIAL NORMALIZATION

  12. SUGRA IPL SUGRA IPL SUGRA IPL Lensing kernel different amount of dark energy at z ~ 1  significant deviation Perturbation growth factor

  13. SUGRA IPL SUGRA IPL TT power spectrum only slight projection effect EE power spectrum

  14. COMPARISON OF B-MODES SPECTRA IPL SUGRA 30% difference in amplitude at peak effect is due to B-modes sensitivity to DE equation of state DERIVATIVE!

  15. GETTING MORE QUANTITATIVE: A FISHER MATRIX ANALYSIS ESTIMATOR OF ACHIEVABLE PRECISION set of parameters αi single spectrum four spectra F-1ij gives marginalized 1-σ error on parameters

  16. dark energy parametrization: Chevallier & Polarski 2001, Linder & Huterer 2005 fixing primordial normalization one has only projection effects on TT,TE,EE spectra B spectrum  amplitude changes!  (sensitivity to dynamics at lower redshifts)

  17. w0 = -1 w∞= -1 ns = 0.96 h0 = 0.72 τ = 0.11 Ωbh2= 0.022 Ωm h2 = 0.11 A = 1 PARAMETERS ΛCDM SUGRA • w0 = -0.9 • w∞= -0.4 • ns = 0.96 • h0 = 0.72 • τ = 0.11 • Ωbh2= 0.023 • Ωm h2= 0.12 • A = 1 EBEX-like experiment

  18. √(F-1)ii 0.1 ΛCDM RESULTS few ·10-2 w0 3·10-3 6·10-2 w’ 3·10-3 5 ·10-2 ns 8·10-5 h0 few·10-2 7·10-4 τ 3·10-3 Ωbh2 2·10-3 2·10-2 Ωmh2 3·10-3 A 7·10-5 SUGRA RESULTS 5·10-4 √(F-1)ii 5.0·10-3

  19. CONCLUSIONS AND FURTHER THOUGHTS • We can extract valuable information from the lensed CMB spectra • The B-modes are the most faithful tracer of the dark energy behaviour at intermediate redshifts and can discriminate among models • We have a computational machine allowing us to predict the lensed spectra of a wide range of models • We expect to be able to rule out or select models thanks to the next generation of CMB polarization-devoted experiments (EBEX, CMBpol, PolarBEar)

  20. CONCLUSIONS AND FURTHER THOUGHTS • We can extract valuable information from the lensed CMB spectra • The B-modes are the most faithful tracer of the dark energy behaviour at intermediate redshifts and can discriminate among models • We have a computational machine allowing us to predict the lensed spectra of a wide range of models • We expect to be able to rule out or select models thanks to the next generation of CMB polarization-devoted experiments (EBEX, CMBpol, PolarBEar)

  21. CONCLUSIONS AND FURTHER THOUGHTS • We can extract valuable information from the lensed CMB spectra • The B-modes are the most faithful tracer of the dark energy behaviour at intermediate redshifts and can discriminate among models • We have a computational machine allowing us to predict the lensed spectra of a wide range of models • We expect to be able to rule out or select models thanks to the next generation of CMB polarization-devoted experiments (EBEX, CMBpol, PolarBEar)

  22. CONCLUSIONS AND FURTHER THOUGHTS • We can extract valuable information from the lensed CMB spectra • The B-modes are the most faithful tracer of the dark energy behaviour at intermediate redshifts and can discriminate among models • We have a computational machine allowing us to predict the lensed spectra of a wide range of models • We expect to be able to rule out or select models thanks to the next generation of CMB polarization-devoted experiments (EBEX, CMBpol, PolarBEar)

  23. CONCLUSIONS AND FURTHER THOUGHTS • We can extract valuable information from the lensed CMB spectra • The B-modes are the most faithful tracer of the dark energy behaviour at intermediate redshifts and can discriminate among models • We have a computational machine allowing us to predict the lensed spectra of a wide range of models • We expect to be able to rule out or select models thanks to the next generation of CMB polarization-devoted experiments (EBEX, CMBpol, PolarBEar)

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