CMB observations and results Dmitry Pogosyan University of Alberta Lake Louise, February, 2003 Lecture 1: What can Cosmic Microwave Background tell us about the Universe ? A theoretical introduction. Lecture 2: Recent successes in the mapping of CMB anisotropy: what pre-WMAP and WMAP data reveals.

∆T/T ~ 10 -5

Sachs-Wolfe Effect Acoustic Oscillations Drag Damping Curvature Doppler Tensors Reionization Phenomenology of the Angular Power Spectrum large small

Error origins – noise and ‘cosmic variance’ Cosmic Variance ~ C l / √fsky Noise

Relikt, 1983 (USSR) First CMB anisotropy data actively used to restrict cosmological models Quadrupole dT/T < 4 x Many models where dismissed for failing this limit – hot (massive neutrino) dark matter, late decaying neutrinos ….

COBE-DMR, 1992 First detection of anisotropy large angular scale l < 20 growing initial slope ns=1.2  0.2 Low quadrupole power

Search for the first acoustic peak: TOCO 1998 Boomerang NAmerica, 1997

Mapping acoustic oscillations: Boomerang Maxima DASI 2001

2002 CBI – damping tail Archeops – low l link to COBE ACBAR - medium-high l DASI – detection of polarization

Pre WMAP parameters (Jan 2003)

Deficiencies Covering only part of the sky leads to high cosmic variance uncertainties. (Noise is not an issue at l < 1000) Patched coverage of the angular scales enhances role of systematics (e.g., calibration and beam uncertainties) which dominates analysis. As the result – limited success of breaking some degeneracies –  c –  8 as predicted from CMB –  c – ns –  c – gravitational waves

Wilkinson Microwave Probe (WMAP) – launch June 2001, first year data release – Feb 11, % of full sky 5 frequency channels at Ghz First 1year data – sky is covered twice Each pixel observed ~3000 times. Cosmic variance limited up to l~ % calibration uncertainty

WMAP high S/N, high resolution CMB map of the full sky

Joint pre-WMAP  k =  0.05  b =   cdm = 0.12  0.02 n s = 0.95  0.04  c < WMAPext  k =  0.02  b =   cdm =  h = 0.71  0.04 n s = runs  c = 0.17  0.04 WMAP alone  k =  0.05  b =   cdm = 0.14  0.02 h = 0.72  0.05 n s = 0.99  0.04  c = 0.15  0.07

Measurement of TE polarization Prove of adiabatic perturbation origin (TE anticorrelation at ~ 100)  c determination from TE enhancement at l < 20. WMAP new advances – TE:  c, adiabaticity

CMB Polarization Full description of radiation is by polarization matrix, not just intensity – Stockes parameters, I,Q,U,V Why would black-body radiation be polarized ? Well, it is not in equilibrium, it is frozen with Plankian spectrum, after last Thompson scattering, which is a polarizing process. But only, because there is local quadrupole anisotropy of the photon flux scattered of electron. Thus, P and dT/T are intimately related, second sources first (there is back-reaction as well). There is no circular polarization generated, just linear – Q,U. Level of polarization ~10% for scalar perturbations, factor of 10 less for tensors. Thus needed measurements are at dT/T~10 -6 – l evel. As field on the sky – B, E modes (think vectors, but in application to second rank tensor), distinguished by parity.

WMAP new advances – extending the parameter list Do we need ever precise determination of the parameters ? Yes, if we want to explore larger parameter space., WMAP: –Running ns – positive slope at low l, negative at higher l Recall COBE-DMR, it also preferred n~1.2 ! Also, low quadrupole – hint to new physics ? –Gravitational wave (tensor) contribution to dT/T is small < 0.72 of scalar component

“ The Seven Pillars ” of the CMB (of inflationary adiabatic fluctuations)  Large Scale Anisotropies  Acoustic Peaks/Dips  Gaussianity Polarization, TE correlation Damping Tail Secondary Anisotropies Gravity Waves, B-type polarization pattern Minimal Inflationary parameter set Quintessesnce Tensor fluc. Broken Scale Invariance

BOOMERANG Cosmic Background Imager (CBI) ACBAR