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 band powers, in combination with the COBE/Differential Microwave Radiometer, to explore the space of quintessence parameters: the quintessence energy density Ωphgr and equation of state wphgr. We restrict our analysis to flat, scale-invariant, inflationary adiabatic models. We find that this simple class of inflationary models, with a quintessence component Ωphgr lesssim 0.7, -1 ≤ wphgr lesssim -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.
