Implications for quintessence models from MAXIMA-1 and BOOMERANG-98

Abstract

Prompted by the recent MAXIMA-1 and BOOMERANG-98 measurements of the cosmic microwave background (CMB) anisotropy power spectrum, and motivated by the results from the observation of high-redshift Type Ia supernovae, we investigate CMB anisotropies in quintessence models in order to characterize the nature of the dark energy today. We perform a Bayesian likelihood analysis, using the MAXIMA-1 and BOOMERANG-98 published bandpowers, in combination with COBE/DMR, to explore the space of quintessence parameters: the quintessence energy density Ω_ϕand equation of state w_ϕ. We restrict our analysis to flat, scale-invariant, inflationary adiabatic models. We find that this simple class of inflationary models, with a quintessence component Ω_ϕ< ~0.7, -1 < = w_ϕ< ~-0.5, is in good agreement with the data. Within the assumptions of our analysis, pure quintessence models seem to be slightly favored, although the simple cosmological constant scenario is consistent with the data.