Recent results from BOOMERANG-98 and MAXIMA-1, taken together with COBE DMR, provide consistent and high signal-to-noise measurements of the cosmic microwave background power spectrum at spherical harmonic multipole bands over 2

We present a multiwavelength analysis of a sample of four hot (T X > 8 keV) X-ray galaxy clusters (A1689, A2261, A2142, and A2390) using joint AMiBA Sunyaev-Zel'dovich effect (SZE) and Subaru weak lensing observations, combined with published X-ray temperatures, to examine the distribution of mass and the intracluster medium (ICM) in massive cluster environments. Our observations show that A2261 is very similar to A1689 in terms of lensing properties. Many tangential arcs are visible around A2261, with an effective Einstein radius ∼ 40 ′′ (at z ∼ 1.5), which when combined with our weak lensing measurements implies a mass profile well fitted by an NFW model with a high concentration c vir ∼ 10, similar to A1689 and to other massive clusters. The cluster A2142 shows complex mass substructure, and displays a shallower profile (c vir ∼ 5), consistent with detailed X-ray observations which imply recent interaction. The AMiBA map of A2142 exhibits an SZE feature associated with mass substructure lying ahead of the sharp north-west edge of the X-ray core suggesting a pressure increase in the ICM. For A2390 we obtain highly elliptical mass and ICM distributions at all radii, consistent with other X-ray and strong lensing work. Our cluster gas fraction measurements, free from the hydrostatic equilibrium assumption, are overall in good agreement with published X-ray and SZE observations, with the sample-averaged gas fraction of f gas (< r 200 ) = 0.133 ± 0.027, for our sample with M vir = (1.2 ± 0.1) × 10 15 M ⊙ h −1 . When compared to the cosmic baryon fraction f b = Ω b /Ω m constrained by the WMAP 5-year data, this indicates f gas,200 / f b = 0.78 ± 0.16, i.e., (22 ± 16)% of the baryons are missing from the hot phase of clusters.

We discuss the cosmological implications of the new constraints on the power spectrum of the Cosmic Microwave Background Anisotropy derived from a new high resolution analysis of the MAXIMA-I measurement. The power spectrum indicates excess power at ℓ ∼ 860 over the average level of power at 411 ≤ ℓ ≤ 785. This excess is statistically significant on the ∼ 95% confidence level. Its position coincides with that of the third acoustic peak as predicted by generic inflationary models, selected to fit the first acoustic peak as observed in the data. The height of the excess power agrees with the predictions of a family of inflationary models with cosmological parameters that are fixed to fit the CMB data previously provided by BOOMERANG-LDB and MAXIMA-I experiments.Our results, therefore, lend support for inflationary models and more generally for the dominance of adiabatic coherent perturbations in the structure formation of the Universe. At the same time, they seem to disfavor a large variety of the non-standard (but inflation-based) models that have been proposed to improve the quality of fits to the CMB data and consistency with other cosmological observables.Within standard inflationary models, our results combined with the COBE-DMR data give best fit values and 95% confidence limits for the baryon density, Ω b h 2 ≃ 0.033±0.013, and the total density, Ω = 0.9 +0.18 −0.16 . The primordial spectrum slope (n s ) and the optical depth to the last scattering surface (τ c ) are found to be degenerate and to obey the relation n s ≃ (0.99 ± 0.14) + 0.46τ c , for τ c ≤ 0.5 (all 95% c.l.).

We extend the analysis of the MAXIMA-1 cosmic microwave background (CMB) data to smaller angular scales. MAXIMA, a bolometric balloon experiment, mapped a 124 deg 2 region of the sky with 10 ′ resolution at frequencies of 150, 240 and 410 GHz during its first flight. The original analysis, which covered the multipole range 36 ≤ ℓ ≤ 785, is extended to ℓ = 1235 using data from three 150 GHz photometers in the fully cross-linked central 60 deg 2 of the map. The main improvement over the original analysis is the use of 3 ′ square pixels in the calculation of the map. The new analysis is consistent with the original for ℓ < 785. For ℓ > 785, where inflationary models predict a third acoustic peak, the new analysis shows power with an amplitude of 56 ± 7 µK at ℓ ≃ 850 in excess to the average power of 42 ± 3 µK in the range 441 < ℓ < 785.Subject headings: cosmic microwave background -cosmology: observations 2. telescope beams

We discuss MAXIPOL, a bolometric balloon-borne experiment designed to measure the E-mode polarization of the cosmic microwave background radiation (CMB). MAXIPOL is the first bolometric CMB experiment to observe the sky using rapid polarization modulation. To build MAXIPOL, the CMB temperature anisotropy experiment MAXIMA was retrofitted with a rotating half-wave plate and a stationary analyzer. We describe the instrument, the observations, the calibration, and the reduction of data collected with 12 polarimeters operating at 140 GHz and with a FWHM beam size of 10 0 . We present maps of the Q and U Stokes parameters of an 8 deg 2 region of the sky near the star UMi. The power spectra computed from these maps give weak evidence for an EE signal. The maximum likelihood amplitude of '(' þ 1)C EE ' /2 is 55 þ51 À45 K 2 (68%), and the likelihood function is asymmetric and skewed positive such that with a uniform prior the probability that the amplitude is positive is 96%. This result is consistent with the expected concordance ÃCDM amplitude of 14 K 2 . The maximum likelihood amplitudes for '(' þ 1)C BB ' /2 and '(' þ 1)C EB ' /2 are À31 þ31 À19 and 18 þ27 À34 K 2 (68%), respectively, which are consistent with zero. All of the results are for one bin in the range 151 ' 693. Tests revealed no residual systematic errors in the time or map domain. A comprehensive discussion of the analysis of the data is presented in a companion paper.