COSMOLOGICAL-PARAMETER DETERMINATION WITH MICROWAVE BACKGROUND MAPS

The angular power spectrum of the cosmic microwave background (CMB) co ntains information on virtually all cosmological parameters of interes t, including the geometry of the Universe (Omega), the baryon density, the Hubble constant (h), the cosmological constant (Lambda), the numb er of light neutrinos, the ionization history, and the amplitudes and spectral indices of the primordial scalar and tensor perturbation spec tra. We review the imprint of each parameter on the CMB. Assuming only that the primordial perturbations were adiabatic, we use a covariance -matrix approach to estimate the precision with which these parameters can be determined by a CMB temperature map as a function of the fract ion of sky mapped, the level of pixel noise, and the angular resolutio n. For example, with no prior information about any of the cosmologica l parameters, a full-sky CMB map with 0.5 degrees angular resolution a nd a noise level of 15 mu K per pixel can determine Omega, h, and Lamb da with standard errors of +/-0.1 or better, and provide determination s of other parameters which are inaccessible with traditional observat ions. Smaller beam sizes or prior information on some of the other par ameters from other observations improves the sensitivity. The dependen ce on the underlying cosmological model is discussed.