Astroparticles and Primordial Cosmology_S3

Astroparticles and Primordial Cosmology

Contact: Pr. J.-P. Ernenwein

 

Astroparticles (20 h)

0. Introduction: Historical aspects: from early steps to the current domain of Astroparticles

1. Sources and transport of particles in the Universe
• Sources and their vicinity: production and acceleration mecanisms
• Examples of sources: Supernova Remnants, Binary systems, Active Galactic Nuclei, Gamma-ray bursters.
• Transport: General aspects, case of cosmic-ray interaction with the CMB: "GZK cut-off", case of propagation of gamma-rays.

2. Cosmic rays at Earth
• Primary cosmic rays: Composition and Flux. Experimental aspects: satellites, balloons.
• Secondary cosmic rays: Atmospheric showers, secondary particles at sea level and underground. Experimental aspects: detection ( examples: KASCADE, AUGER).

3. Gamma-ray astronomy
• Methods: Satellites: example of FERMI; Ground based detectors: Imaging Atmospheric Cherenkov Telescopes (example of H.E.S.S.), arrays of detectors ( example of HAWC),
• Multi-wavelength studies: combining observations from radio to gamma rays.

4. Other messengers
• Search for astrophysical neutrinos: neutrino telescopes: ICECUBE, ANTARES,
• Gravitational waves: LIGO, VIRGO,
• Multi-messenger aspects.

5. Dark Matter (DM)
• Phenomenological context: why the DM ? What is DM ?
• Detection techniques and current limits: direct and indirect detection.

Primordial Cosmology (20 h)

1. Thermodynamics of primordial universe:
• Friedmann models (recap).
• The early universe: equilibrium thermodynamics, entropy, phase transitions and thermal history.
• Big-bang nucleosynthesis: Numerical modelling and comparison to recent observations,
• Thermodynamics in expanding universe: Boltzmann equation, freeze-out and origin of species (CDM, HDM, WIMPS), out-of-equilibrium decay, recombination. Neutrino cosmology. Baryogenesis.
 Applications (learning-by-doing): Lithium abundance, abundance of WIMPZILLA's and UHECR, Lee-Weinberg bound.

2. Quantum fluctuations during inflation:
• Klein-Gordon equation in expanding universe, linear perturbations and quantization of massless and massive inflaton, gauge invariance.
• Metric fluctuations, gauge invariance, quantum-to-classical transition, curvature and matter perturbations, gravitational waves, scalar and tensor power spectra, consistency relations.
• Primordial non-gaussianities (fNL, gNL). Reheating, pre-heating.
 Applications (learning-by-doing): numerical solution of KG equation for some
inflationary model (power-law, lambda phi^4 , hybrid, natural), study of the dynamical system.

3. Cosmic Microwave Background:
• Recombination and decoupling.
• Monopole, dipole and residual fluctuations. Spherical statistics.
• Temperature fluctuations: kinetic description, Sachs-Wolfe plateau, acoustic peaks, secondary anisotropies. Sources of noise and map-making: dust absorption, synchrotron radiation and Bremsstrahlung. Polarization: E- and B-modes, gravitational waves.
  Applications (learning-by-doing): use of Boltzmann codes (CAMB, CLASS) to simulate CMB spectra and maps.

4. From post-recombination Universe to large-scale structure:
• From CMB to dark ages, ionization sources of H and He. Lyman systems and LyA-forest, IGM fluctuations, Gunn-Peterson effects. 21-cm cosmology.
• Density and velocity fields: Jeans modelling, Zel'dovich approximation.
• Statistics of fluctuations on large scales: counts, correlation functions, power spectrum.
• Spherical collapse, mass function, bias; halo model.
  Applications (learning-by-doing): numerical solution of Jeans equation in neutrino cosmology, estimation of massive clusters' counts in cosmologies with pNG (fNL).

5. Statistical analysis of cosmological models:
• Combination of probes to extract cosmological parameters. Degeneracies.
• Frequentist and Bayesian approaches: grid method, gradient method, MCMC.
• Forecasts: Fisher analysis and Monte Carlo simulation. Modelling of systematics.
 Applications (learning-by-doing): fitting the Hubble diagram from supernovae
(Union 2) and CMB TT power spectrum (WMAP or Planck), Fisher matrix of
cluster counts for fNL.

 

References:

– P. Peter, J.-P. Uzan, "Primordial Cosmology", Oxford University Press (2013)
– D. Lyth, A. Liddle, "The Primordial Density Perturbation: Cosmology, Inflation and the Origin of Structure", Cambridge University Press (2009)
– S. Dodelson, "Modern Cosmology", Elsevier (2003)
– M Spurio, “Particles and Astrophysics, a Multi-Messenger Approach”, Springer (2015), ISBN 978-3-319-08050-5
– T.K. Gaisser, “Cosmic Rays and Particle Physics”, Cambridge University Press (1990)