COSMIC MICROWAVE BACKGROUND ANISOTROPIES IN COLD DARK-MATTER MODELS WITH COSMOLOGICAL CONSTANT - THE INTERMEDIATE VERSUS LARGE ANGULAR SCALES

We obtain predictions for cosmic microwave background anisotropies at angular scales near 1-degrees in the context of cold dark matter model s with a nonzero cosmological constant, normalized to the COBE-DMR det ection. The results are compared to those computed in the matter-domin ated models. We show that the coherence length of the CMB anisotropy i s almost insensitive to cosmological parameters, and the rms amplitude of the anisotropy increases moderately with decreasing total matter d ensity, while being most sensitive to the baryon abundance. We apply t hese results in the statistical analysis of the published data from th e UCSB South Pole (SP) experiment (Gaier et al. 1992; Schuster et al. 1993). We reject most of the CDM-LAMBDA models at the 95% confidence l evel when both SP scans are simulated together (although the combined data set renders less stringent limits than the Gaier et al. data alon e). However, the Schuster et al. data considered alone, as well as the results of some other recent experiments (MAX, MSAM, Saskatoon), sugg est that typical temperature fluctuations on degree scales may be larg er than is indicated by the Gaier et al. scan. If so, CDM-LAMBDA model s may indeed provide, from the point of view of CMB anisotropies, an a cceptable alternative to flat CDM models.