Microwave Background Constraints on Cosmological Parameters

We use a high-accuracy computational code to investigate the precision withwhich cosmological parameters could be reconstructed by future cosmic microwavebackground (CMB) experiments, in particular the two satellite missions MAP andPlanck Surveyor (COBRAS/SAMBA). We identify several parameter combinations thatcould be determined with a few percent accuracy with MAP and the PlanckSurveyor, as well as some degeneracies among the parameters that cannot beaccurately resolved with the temperature data alone. These degeneracies can bebroken by other astronomical measurements. Polarization measurments cansignificantly enhance the science return of both missions by allowing accuratedetermination of cosmological parameters, by enabling the detection of gravitywaves and by probing the ionization history of the universe. We also addressthe question of how gaussian the likelihood function is around the maximum andwhether gravitational lensing changes the constraints.Comment: Minor changes to match ApJ version. 32 pages, 10 figure