MAXIMA: Observations of CMB anisotropy

This document describes the Millimeter Anisotropy eXperiment IMaging Array (MAXIMA), a balloon-borne experiment measuring the temperature anisotropy of the Cosmic Microwave Background (CMB) on angular scales of 10 ′ to 5°. MAXIMA data are used to discriminate between cosmological models and to determine cosmological parameters.; MAXIMA maps the CMB using 16 bolometric detectors observing in spectral bands centered at 150 GHz, 230 GHz, and 410 GHz, with 10 ′ resolution at all frequencies. The combined receiver sensitivity to CMB anisotropy is ∼40 μK $sec$, the best reported by any CMB experiment. Systematic errors are rejected by using four uncorrelated spatial modulations, multiple independent CMB observations, heavily baffled optics, and strong spectral discrimination. Observation patterns are well cross-linked and optimized for the extraction of cosmological information. Pointing is reconstructed to an accuracy of 1′. Absolute calibration uncertainty of 3–4% is the best achieved by any sub-orbital CMB experiment.; Two MAXIMA flights were launched from the National Scientific Balloon Facility in Palestine Texas in 1998 and 1999. During a total of 8.5 hours of CMB observations, 300 deg2 of the sky were mapped, with ∼50 deg2 overlap between the two flights. The observed region was selected for low foreground emission and post-flight data analysis confirms that foreground contamination is negligible.; Cosmological results are presented from the 1998 flight, MAXIMA-I , in which 122 deg2 of sky were mapped over 3 hours. A maximum likelihood map with 3′ pixelization is obtained from the three most sensitive and best tested detectors. The angular power spectrum derived from this map shows a narrow peak near ℓ = 200, and is consistent with inflationary Big Bang models. Within these models, cosmological parameters are estimated, including total density Ω_tot = $0.9+0.18-0.16$, baryon density Ω_bh2 = 0.033 ± 0.013, and power spectrum normalization C ₁₀ = $690+200-125mK2$. In combination with recent supernova observations, we obtain additional constrains on the matter density Ω_m = $0.32+0.14-0.11$ and the dark energy density Ω_Λ = $0.65+0.15-0.16$. All parameter estimates are presented at 95% confidence.; The final chapter is a discussion CMB polarization anisotropy, including an overview of MAXIPOL, the polarization sensitive follow-up to MAXIMA. Measurements of CMB polarization are an essential complement to those of temperature anisotropy.