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DESY, 30 September 2008 Julien Lesgourgues (CERN & EPFL)

Neutrino cosmology. DESY, 30 September 2008 Julien Lesgourgues (CERN & EPFL). MAIN STREAM DM = CDM + 3 flavor neutrinos, with 2 or 3 massive eigenstates 2 unknown “cosmological parameters”: S m n , IH or NH

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DESY, 30 September 2008 Julien Lesgourgues (CERN & EPFL)

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  1. Neutrino cosmology DESY, 30 September 2008 Julien Lesgourgues (CERN & EPFL)

  2. MAIN STREAM DM = CDM + 3 flavor neutrinos, with 2 or 3 massive eigenstates 2 unknown “cosmological parameters”: Smn , IH or NH detectable negligible SIDE WAYS Sterile, non-thermal, coupled, decaying, mass-varying, …

  3. accélération décélération lente décélération rqpide accélération inflation radiation matière énergie noire Effect of neutrino mass accélération décélération lente décélération rqpide accélération ?

  4. Effect of neutrino mass • Background effect: parameter Wn different from Wcdm (also DM today, but radiation in the past) e.g. increase Wn with fixed Wdm decrease Wcdm postpone M/R equality change CMB peak height (and position) and shape of matter power spectrum P(k) non-degenerate effect for flat LCDM • Effect on perturbations: free-streaming slows down structure formation

  5. Perfect versus free-streaming fluid • Perfect fluid = strongly coupled particles with bulk velocity (in the linear regime: single-valued velocity field) • Free-streaming particles = collisionless particles with f(x,p,t) ≈ f(p,t) p CDM (WIMPS) in the approximation v << c x p |v| = |p| /m = velocity dispersion x HDM (light neutrinos) with 0.01 < v/c < 1

  6. distances RH l a inflation eq time Free-streaming scale acausal wavelength perturbation causal MATTER DOMINATION RADIATION DOMINATION

  7. distances RH l a free-streaming scale (10-4 eV < m < 1 eV) inflation eq time Free-streaming scale maximum comoving f.s.s. acausal wavelength perturbation causal MATTER DOMINATION RADIATION DOMINATION nr heavy light

  8. Effect of neutrino masseson (linear) structure formation dm + H dm = 4pG rmdm expansion gravitational force Below critical scale, neutrinos contribute to expansion but not to gravitational force: dm(a) slows down, [d lndm/d ln a – 1] aSmn .. .

  9. Free-streaming and structure formation a dcdm db J.L. & S. Pastor, Physics Reports [astro-ph/0603494] dn dg metric

  10. Free-streaming and structure formation a dcdm db 1-3/5fn a (fn = wn/wm) dn J.L. & S. Pastor, Physics Reports [astro-ph/0603494] dg metric

  11. Signature of massive neutrinos on P(k) • characteristic shape of matter power spectrum today P(k) = dm2 (today) -8fn (from 3% to 60% for 0.05eV to 1eV) k Light neutrinos step-like suppression

  12. Signature of massive neutrinos on P(k) • linear growth factor sCDM (no DE, no mn) P(k,a)/a2 = (1+z)2 P(k,z) k sCDM no linear growth factor

  13. Signature of massive neutrinos on P(k) • linear growth factor sCDM (no DE, no mn) P(k,a)/a2 = (1+z)2 P(k,z) DE+CDM (no mn) k DE+CDM scale-independent linear growth factor

  14. Signature of massive neutrinos on P(k) • linear growth factor sCDM (no DE, no mn) P(k,a)/a2 = (1+z)2 P(k,z) DE+CDM+HDM k DE+CDM+mn scale-dependent linear growth factor

  15. accélération décélération lente décélération rqpide accélération inflation radiation matière énergie noire currentobservations accélération décélération lente décélération rqpide accélération ? till 2007: best constraints from free-streaming since WMAP-5yr: background effect better seen future: free-streaming more powerful

  16. Bounds on neutrino mass (95% CL) mass bounds from 7-parameter fits (LMDM = minimal LCDM+Mn) + SNIa / BAO + Lya Adapted from J.L. & S. Pastor, Physics Reports 06

  17. Bounds on neutrino mass (95% CL) mass bounds from 7-parameter fits (LMDM = minimal LCDM+Mn) CMB only WMAP5 Dunkley et al. 08 + SNIa / BAO + Lya Adapted from J.L. & S. Pastor, Physics Reports 06

  18. Bounds on neutrino mass (95% CL) mass bounds from 7-parameter fits (LMDM = minimal LCDM+Mn) + background (dA, dL) WMAP5 + BAO (SDSS, 2dF) + + SNIa (SNLS, ESSENCE) Komatsu et al. 08 + SNIa / BAO + Lya Adapted from J.L. & S. Pastor, Physics Reports 06

  19. Bounds on neutrino mass (95% CL) mass bounds from 7-parameter fits (LMDM = minimal LCDM+Mn) + galaxy power spectrum + SNIa / BAO WMAP3 + SDSS-LRG/BAO + 2dF + SNIa Hannestad et al. 07, Kristiansen et al. 07 + Lya Adapted from J.L. & S. Pastor, Physics Reports 06

  20. Bounds on neutrino mass (95% CL) mass bounds from 7-parameter fits (LMDM = minimal LCDM+Mn) + galaxy power spectrum + SNIa / BAO WMAP3 + SDSS-LRG/BAO + 2dF + SNIa Hannestad et al. 07, Kristiansen et al. 07 limited to scales still linear today: + Lya Adapted from J.L. & S. Pastor, Physics Reports 06 suppression effect in power spectrum P(k)

  21. Bounds on neutrino mass (95% CL) mass bounds from 7-parameter fits (LMDM = minimal LCDM+Mn) + Lyman-a forest + SNIa / BAO Adapted from J.L. & S. Pastor, Physics Reports 06 WMAP5 + other CMB + SDSS-LRG/BAO + SNIa + SDSS-Lya Fogli et al. 08

  22. accélération décélération lente décélération rqpide accélération inflation radiation matière énergie noire futuretechniques accélération décélération lente décélération rqpide accélération ?

  23. Weak lensing: galaxy shear tomography COSMOS Map of gravitational potential projected along line-of-sight Future: many dedicated surveys (CFHTLS, DES, SNAP, Pan-STARRS, LSST, Dune, …) Massey et al., Nature 05497, 7 january 2007

  24. Weak lensing: CMB deflection map of gravitational potential projected along line-of-sight, especially around z~3

  25. Weak lensing: theoretical prediction Lensing spectrum (= convergence spectrum) expected power spectrum of lensing potential from sources at z ~ 1100 (CMB) (error for CMBpol) linear from sources at z ~ 0.2, 0.6, … 3.0 (error for LSST) Song & Knox [astro-ph/0312175]

  26. Weak lensing: theoretical prediction Lensing potential spectrum

  27. Weak lensing: observation with Planck JL, Perotto, Pastor, Piat Phys.Rev.D73:045021,2006

  28. Weak lensing: forecasts Perotto et al. 06 Lesgourgues et al. 05 J.L. & S. Pastor, Physics Reports [astro-ph/0603494] Planck+DUNE Kitching et al 08 SNAP Song & Knox 2003 LSST

  29. Other promising techniques • ISW effect induced by free-streaming during MD/DED Detectable with CMB x LSS cross-correlation Ichikawa & Takahashi 05 Lesgourgues, Valkenburg & Gaztanaga 07 • Cluster redshift surveys Wang et al. 05 • 21cm surveys (21cm line emission by residual cosmic hydrogen after reionization) Wyithe &Loeb 08 s=0.006 eV (differentiate NH / IH) Pritchard & Pierpaoli 08 • Lya forests in quasar spectra Gratton et al. 07

  30. Impact of massive neutrinos on non-linear gravitational clustering • … is a crucial to understand, in order to: • Extend analysis of galaxy / cluster/ cosmic shear surveys to larger k • Perform proper analysis of Ly-a / BAO / 21cm data • Properly extract / interpret CMB foregrounds (thermal SZ) • Precisely address small-scale CDM distribution problem (satellites)

  31. Impact of massive neutrinos on non-linear gravitational clustering Brandbyge et al. 0802.3700 [astro-ph] N-body simulations including thermal velocities

  32. Impact of massive neutrinos on non-linear gravitational clustering z=0 Saito, Takada, Taruya 0801.0607 [astro-ph] Semi-analytical method (approximation to one-loop order)

  33. Impact of massive neutrinos on non-linear gravitational clustering Y.Y.Y.Wong 0809.0693 [astro-ph] Semi-analytical method (one-loop order)

  34. accélération décélération lente décélération rqpide accélération inflation radiation matière énergie noire The end accélération décélération lente décélération rqpide accélération ?

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