Constraints on Cosmological Parameters from MAXIMA-1

A. Balbi, P. Ade, J. Bock, J. Borrill, A. Boscaleri, P. de Bernardis, P. G. Ferreira, S. Hanany, V. V. Hristov, A. H. Jaffe, A. T. Lee, S. Oh, E. Pascale, B. Rabii, P. L. Richards, G. F. Smoot, R. Stompor, C. D. Winant, J. H. P. Wu

Published 2000-05-08, updated 2001-09-04Version 3

We set new constraints on a seven-dimensional space of cosmological parameters within the class of inflationary adiabatic models. We use the angular power spectrum of the cosmic microwave background measured over a wide range of \ell in the first flight of the MAXIMA balloon-borne experiment (MAXIMA-1) and the low \ell results from COBE/DMR. We find constraints on the total energy density of the universe, \Omega=1.0^{+0.15}_{-0.30}, the physical density of baryons, \Omega_{b}h^2=0.03 +/- 0.01, the physical density of cold dark matter, \Omega_{cdm}h^2=0.2^{+0.2}_{-0.1}$, and the spectral index of primordial scalar fluctuations, n_s=1.08+/-0.1, all at the 95% confidence level. By combining our results with measurements of high-redshift supernovae we constrain the value of the cosmological constant and the fractional amount of pressureless matter in the universe to 0.45<\Omega_\Lambda<0.75 and 0.25<\Omega_{m}<0.50, at the 95% confidence level. Our results are consistent with a flat universe and the shape parameter deduced from large scale structure, and in marginal agreement with the baryon density from big bang nucleosynthesis.