New paper! We describe observational evidence for dark energy which is independent of the supernova surveys, and therefore not subject to systematic effects from dust, evolution or exotic particle physics (such as photon to axion decay). The figure below shows the likelihood, given best measurements of the age of the universe, the Hubble parameter and the matter fraction, that there was NOT a cosmological epoch with equation of state paramater w < w* (w = pressure / energy density). As you can see, an epoch with a repulsive energy component (w < -1/3) is highly likely. The three curves represent different assumptions about observational errors.
astro-ph/0612106Precision cosmological measurements: independent evidence for dark energy
Authors: Greg Bothun, Stephen D.H. Hsu, Brian Murray
Comments: 4 pages, revtex, 3 figures
We examine whether observations independent of type Ia supernova surveys are sufficient to imply the existence of dark energy. We find that best measurements of the age of the universe $t_0$, the Hubble parameter $H_0$ and the matter fraction $\Omega_m$ strongly favor the existence of a repulsive, acceleration-causing ($w < -1/3$) component of energy if the universe is nearly flat.
