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Astroparticle Physics (1/3)

What is Astroparticle Physics ? Big Bang Nucleosynthesis Cosmic Microwave Background Dark matter, dark energy High energy astrophysics. Astroparticle Physics (1/3). Nathalie PALANQUE-DELABROUILLE CEA-Saclay CERN Summer Student Lectures, August 2006. What is Astroparticle Physics ?

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Astroparticle Physics (1/3)

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  1. What is Astroparticle Physics ? Big Bang Nucleosynthesis Cosmic Microwave Background • Dark matter, dark energy • High energy astrophysics Astroparticle Physics (1/3) Nathalie PALANQUE-DELABROUILLE CEA-Saclay CERN Summer Student Lectures, August 2006 • What is Astroparticle Physics ? Big Bang Nucleosynthesis Cosmic Microwave Background • Dark matter, dark energy • High energy astrophysics

  2. Astroparticle Physics? - Composition of the Universe ? - Evolution of the Universe ? - Extreme phenomena ? Particle physics Astronomy Cosmology ASTROPARTICLE PHYSICS

  3. Evolution of the Universe Time T (K) 1010 BBN (nuclei) Recombination (atom) 103 Time t T(K) ~ 1010 / t1/2(s) Radiation dominated U. 1 mn 3.105 y

  4. Primary cosmic ray Unidentified sources Today’s universe Astroparticle  high energy phenomena, cosmic accelerators Gamma rays Cosmic rays 3rd EGRET catalog Neutrinos many astrophysical sources (sun, galactic center, AGN…)  Lecture 3

  5. Multi-wavelength universe The different faces of the Milky Way

  6. Content of the universe A2218 Dark matter  Lecture 2 Dark energy

  7. Evolution of the Universe Time T (K) 1010 BBN (nuclei) Recombination (atom) 103 Time t T(K) ~ 1010 / t1/2(s) Radiation dominated U. 1 mn 3.105 y

  8. Lecture outline • What is Astroparticle Physics ? Big Bang Nucleosynthesis Cosmic Microwave Background • Dark matter, dark energy • High energy astrophysics

  9. BBN Elements H He Li Be METALS Which elements ?

  10. Age < 1s, T > 1 MeV Collisions maintain thermal equilibrium Proton - neutron conversion Maxwell-Boltzmann distribution : N  m3/2 exp - mc2 kBT n p N (neutron) N (proton) = ~ e mc2/kT ~ 1 n p  0 as T  0 BUTfreeze-out (m = 1.3 MeV)

  11.    n-p freeze-out - Weak reaction n  p rate: Gweak = ns|v|  GF2 T5 (n  T3 ands  GF2 T2) - Expansion rate: H = a/a  r1/2with r  g* T4 (Stefan’s law) so H g*1/2 T2 . 3 Gweak T • Freeze-out when Gweak~ H with ~ H 0.8 MeV  drop-out of equilibrium at T ~ 0.8 MeV n p = e m/kT = e -(1.3 MeV / 0.8 MeV)~ 0.2

  12. E Deuterium bottleneck nB small  2-body reactions only - - Formation of D Binding Energy (D) = 2.2 MeV - g energy distribution nB / ng ~ 10-10  D photo-disintegrated Tail of high energy photons prevents formation of Deuterium until T ~ 0.1 MeV

  13. H abundance ~ 0.75 t=1-3 mn, T=0.3-0.1 MeV - neutron decay:  n/p ~ (n/p)0 e-(t/) n/p ~ 1/7 - Deuterium (all n): - Helium (all D ie. all n + equal number of p): 2n Helium abundance ~ ~ 0.25 n+p h = nB/ng D bottlenecklasts less n/p  He 

  14. Heavier elements - BBN Li5  He4+p He5  He4+n Be8  He4+He4 No A=5, A=8 stable nuclei + 2-body reactions only BBN essentially STOPS at He4 He4+H3  Li7+g He4+He3  Be7+g Be7+g Li7+p Trace amounts of 3Li7, 4Be7:

  15. Heavier elements - Stars Produced in stars (high densities  triple alpha reactions allowed) Spread in ISM by SN explosions Crab nebula (SN II)

  16. Big Bang Nucleosynthesis Hot stars Supernova explosions Cosmic-ray interactions on inter-stellar medium Origin of elements formed in:

  17. Observational constraints • - Stars are net producers of He4 and metals •  use metal poor stars • upper limit on primordial abundance of He4 (and on h) • D weakly bound • measure in ISM • lower limit on primordial abundance of D (upper limit on h) • D burnt to He3 and He3 produced by stars • D+He3 increases with time upper limit on D+He3 ie lower limit on h • Li7 very fragile, burnt in stars •  use old metal poor stars, require Li6 (more fragile)

  18. CMB: ng = 411 cm-3 h = nB/ng = (41).10-10 nBmB rB WB = = 3H2/8pG rc WB h702~ 0.04 Abundances Observational concordance Agreement of abundances over 10 orders of magnitude  Major success of Big-Bang h

  19. He mass fraction BBN and neutrinos H g*1/2 T2 (remember?) where g* includes relativistic ’s so NnH  sooner freeze-out  n/p  He4 upper limit on He4 Nn = 3

  20. LEP and light neutrinos Nn = 2.994  0.012

  21. Lecture outline • What is Astroparticle Physics ? Big Bang Nucleosynthesis Cosmic Microwave Background • Dark matter, dark energy • High energy astrophysics

  22. Galaxies, clusters CMB observable observable Back to thermal history Density perturbations (inflation?) t = 10-35 s Matter domination t ~ 2000 yrs t ~ 300000 yrs Recombination: p+e-  H+g Matter: Gravitational collapse Photons: Free propagation

  23. End of opaque Universe Multiple scatterings of g on e- produces “thermal” spectrum at T = 3000 K (z ~ 1100 = a0 / arec) Cannot see further back “Uniform” background at T0 = 2.7 K

  24. Discovery Discovered in 1965 as “excess noise” (Nobble Prize in 1978) 25 years later Bell Labs COBE 1992 Bell Labs Wilson Penzias (+ Robert Dicke)

  25. COBE sky maps T = 2.7 K DT = 3.4 mK (after subtraction of constant emission) DT = 18 mK (after subtraction of dipole)

  26. COBE sky maps scale 0-4 K: very homogeneous  cosmological origin Yet, regions > 1° apart never in causal contact Inflation ? z t LSS 103 x 3.105 qLSS ~ rad ~1° 14.109 t now

  27. COBE sky maps Doppler effect due to motion of Earth w.r.t. CMB (v = 370 km/s towards Virgo) Anisotropies : potential wells Early seeds for structure formation? (+ foregrounds)

  28. Anisotropies • Before recombination, Universe = plasma of free e- and protons • Oscillations due to opposite effects of • - gravity • - pressure • Presented as a power spectrum l(l-1)Cl(power) cosmology l~ 200/q (deg)

  29. Anisotropies • Before recombination, Universe = plasma of free e- and protons • Oscillations due to opposite effects of • - gravity • - pressure • Presented as a power spectrum l(l-1)Cl(power) cosmology l~ 200/q (deg)

  30. Max. scale of anisotropies Limited by causality (remember?)  maximum scale  Max scale relates to total content of Universe Wtot (= WM+W)

  31. 2nd generation satellite COBE (7 degree resolution) WMAP (0.25 degree resolution) (l  20) (l 700)

  32. WMAP on its way to L2 Back to back primary mirrors shield WMAP • Very low temperature signal •  Need shielding from • Sun, Earth, Moon, (Jupiter) • Lagrange point L2: position • of co-rotation with Earth •  Stability of conditions • Measure of T differences • 5 frequency channels • Foreground removal (90 GHz) Launch: Jun. 2001 First results: 2003

  33. Cosmological parameters  b h2 = m h2 = h = … ns = 8 = 0.0223 +/-0.001 0.13 +/-0.01 0.73 +/- 0.03 … 0.95 +/- 0.02 0.74 +/- 0.06 Typically ± 5-10% + H0 from HST m= = 0.24 +/- 0.04 0.72 +/- 0.04

  34. 20 GHz 70 GHz 30 GHz 90 GHz 40 GHz Beyond WMAP - More frequency channels - Improved resolution Iound removal Weighted sum

  35. Beyond WMAP - More frequency channels - Improved resolution - Polarization  WMAP 1 an WMAP 1 an + CBI + ACBAR WMAP 3 ans (avec EE)

  36. -  LFI & HFI HEMTS Bolometers Planck - Freq coverage from 30 to 850 GHz (9 channels) - Polarization sensitive - Launch foreseen spring 2008

  37. Next lecture ! Conclusions… • Determinations of WB (~ 4%) from • BBN (age ~ 1 mn) and • CMB (age ~ 300 000 yrs) • agree ! • WB (~ 4%) Wm (~ 28%) • Non baryonic matter • Wm (~ 28%) Wtot (~ 1) •  Confirmation of WL

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