We review the physical processes that are thought to produce anisotropy in the cosmic microwave background, focusing primarily (but not exclusively) on the effects of acoustic waves in the early Universe. We attempt throughout to supply an intuitive, physical picture of the key ideas and to elucidate the ways in which the predicted anisotropy depends on cosmological parameters such as Ω0 and h....

The cosmic microwave background (CMB) is a remarkably distortionless blackbody, and this strongly constrains the amount of energy that can have been injected at high redshift, thereby limiting the role that hydrodynamical amplification can have played in cosmic structure formation. The current data on primary anisotropies (those calculated using linear response theory) provide very strong suppo...

The Cosmic Microwave Background (CMB), which permeates the entire Universe, is the radiation left over from just 380,000 years after the Big Bang. On very large scales, the CMB radiation field is smooth and isotropic, but the existence of structure in the Universe – stars, galaxies, clusters of galaxies, . . . – suggests that the field should fluctuate on smaller scales. Recent observations, fr...

W e present pre l iminary measurements of t h e l i n e a r p o l a r i z a t i o n of t h e cosmic microwave background ( 3 ° K blackbody) r a d i a t i o n . These ground-based measurements are made a t 9 mm wavelength. We f i n d no evidence f o r l i n e a r p o l a r i z a t i o n , and se t an upper l i m i t f o r a po la r i zed component of 0.8 m°K with a 95% confidence level. This imp...

4 1 Standard framework 5 1.1 Big bang models . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 The cosmic microwave background . . . . . . . . . . . . . . . . . . 10 2 Characterizing early Universe fluctuations 15 2.1 Density fluctuations . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.2 CMB temperature fluctuations . . . . . . . . . . . . . . . . . . . . . 18 2.3 Fluctua...

— A major goal of upcoming experiments measuring the Cosmic Microwave Background Radiation (CMBR) is to reveal the subtle signature of inflation in the polarization pattern which requires unprecedented sensitivity and control of systematics. Since the sensitivity of single receivers has reached fundamental limits future experiments will take advantage of large receiver arrays in order to signif...

We present the results of calculations of the cosmic AGN background spectrum from 3 keV (4 × 10μm) to 1000μm. These computations make use of the measured X-ray luminosity function and its evolution, as well as fits from synthesis models of the cosmic X-ray background (CXB) to predict the AGN contribution to the cosmic infrared background (CIRB) for different models of the location and distribut...

The purpose of the Cosmic Background Radiation (CBR) experiments is to measure the temperature anisotropy via the autocorrelation function. The partial wave l1 corresponding to the first Doppler peak caused by baryonphoton oscillations at the surface of last scattering depends on the present density Ω0 and the cosmological constant contribution ΩΛ. We discuss this dependence on the basis of per...

Radio interferometers are well suited to studies of both total intensity and polarized intensity fluctuations of the cosmic microwave background radiation, and they have been used successfully in measurements of both the primary and secondary anisotropy. Recent observations with the Cosmic Background Imager operating in the Chilean Andes, the Degree Angular Scale Interferometer operating at the...

Scaling properties of the cosmic microwave background (CMB) radiation are studied using satellite (COBE-DMR maps), balloonborne and ground-based (combined QMASK map) data. Quantitative consistency is found between the multiscaling properties of the COBE-DMR and QMASK CMB maps. Surprisingly, it is found that the observed CMB temperature multiscaling resembles quantitatively the multiscaling prop...