Constraints on Cosmological Parameters from MAXIMA-1

Abstract

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 in the first flight of the MAXIMA balloon-borne experiment (MAXIMA-1) and the low results from COBE/DMR. We find constraints on the total energy density of the universe, Ω = 1.0 +0.15 −0.30 , the physical density of baryons, Ω b h 2 = 0.03 ± 0.01, the physical density of cold dark matter, Ω 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 < Ω Λ < 0.75 and 0.25 < Ω 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. Subject headings: cosmic microwave background-cosmology: observations-large-scale structure of universe

Constraints on neutrino degeneracy from the cosmic microwave background and primordial nucleosynthesis

“…The ξ νµ,τ = 0 non-degenerate solution is only the preferred minimum, for all values of Ω Λ , when h ≤ 0.70. This is consistent with the results of [45,46]. …”

“…This remains true for the likelihood analysis based upon a MAXIMA-1 data [45] which indicates Ω b h 2 = 0.030 +0.018 −0.010 (2σ). However, in the most recent data sets from BOOMERANG [26] and DASI [27] the second peak has become much better defined.…”

Beyond the cosmological standard model

“…the minima of the effective potential at the object and ambient density, respectively. Assuming that the coupling function takes the form (5.10), the scalar equation of motion (5.8) for a static and spherically-symmetric background reduces to 15) where the density ρ(r) is given by…”

“…Indeed, in the last decade the basic parameters of the accelerating universe are well measured even without using supernova data-providing a powerful consistency check. The two other powerful methods that have been used to measure the geometry of the universe are: the cosmic microwave background (CMB) [13][14][15][16][17][18][19][20][21][22] and the Baryonic Acoustic Oscillation (BAO) feature in the galaxy power spectrum [23][24][25][26][27][28][29][30]. In fact, since measurement of q 0 only constrains the linear combination 1 2 Ω m − Ω Λ , these measurements are a very powerful tool in breaking the degeneracy between these two parameters.…”

“…There is overwhelming observational evidence that the universe is undergoing accelerated expansion from observations of type Ia supernovae [1][2][3][4][5][6][7][8][9][10][11][12], from Cosmic Microwave Background measurements [13][14][15][16][17][18][19][20][21][22], and from detailed studies of large-scale structure [23][24][25][26][27][28][29][30]. All of the measurements are in good agreement, with all data consistent with a Λ-cold dark matter (ΛCDM) cosmology [31,32], with a value of the cosmological constant of about Λ obs.…”