Cosmic Microwave Background Anisotropy at Degree Angular Scales and the Thermal History of the Universe

摘要

We study the anisotropy of the cosmic microwave background (CMB) in cold\udand mixed dark matter (CDM and MDM) models, with non--scale-invariant\udprimordial power spectra (i.e., n{\ne1) and a late, sudden reionization\udof the intergalactic medium at redshift zrh. We test these models\udagainst recent detections of CMB anisotropy at large and intermediate\udangular scales. We find that current CMB anisotropy measurements cannot\uddiscriminate between CDM and MDM models. Our likelihood analysis\udindicates that models with blue power spectra (n \~{}= 1.2) and a\udreionization at zrh \~{} 20 are most consistent with the anisotropy data\udconsidered here. Without reionization our analysis gives 1.0 \lt= n\ud\lt= 1.26 (95\% confidence limit) for Omega b = 0.05.\ud}