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

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 Omega (phi) and equation of state w(phi). We restrict our analysis to flat, scale-invariant, inflationary adiabatic models. We find that this simple class of inflationary models, with a quintessence component Omega (phi) less than or similar to 0.7, -1 less than or equal to w(phi) less than or similar to 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.