[天体物理、宇宙学及物理学电子书合辑].cosmic.microwave.background.observables详解.ppt

Cosmic Microwave Background Carlo Baccigalupi, SISSA CMB lectures at TRR33, see the complete program at darkuniverse.uni-hd.de/view/Main/WinterSchoolLecture5 These lectures are available in pdf format at people.sissa.it/~bacci/work/lectures CMB observables Outline Generalities and historical remarks Cosmological fossils Total intensity and polarization: T, E, B Angular power spectra Status of the CMB observations Suggested lectures Generalities and historical remarks Expanding universe ? CMB compression in the early stages of an expanding universe causes lots of radiation arising from thermonuclear explosions Reactions are rapid enough to achieve thermalization and a black body spectrum It is possible to compute the rarefaction caused by the expansion since that epoch The relic radiation is predicted to peak in microwaves, temperature of a few Kelvin, known today as the Cosmic Microwave Background (CMB, Gamow et al. 1948) Discovery CMB: where and when? Opacity: λ = (neσT)-1 ? horizon Decoupling: λ ≈ horizon Free streaming: λ ? horizon Cosmological expansion, Thomson cross section and electron abundance conspire to activate decoupling about 300000 years after the Big Bang, at about 3000 K CMB photon temperature A postcard from the big bang From the Stephan Boltzmann law, regions at high temperature should carry high density The latter is activated by perturbations which are intrinsic of the fluid as well as of spacetime Thus, the maps of the CMB temperature is a kind of snapshot of primordial cosmological perturbations COsmic Background Explorer From COBE to the Wilkinson Microwave Anisotropy Probe About 20 years of insight into one of the most important observables in physics Lots of experiments, from ground as well as the stratosphere A fantastic technological and data analysis progress, in parallel to theory lambda.gfsc.nasa.gov Cosmological fossils CMB physics: Boltzmann equation CMB physics: Boltzmann equation CMB physics: metric CMB Physics: Compton sc