Probing Dark Energy Using Baryonic Oscillations in the Galaxy Power Spectrum as a Cosmological Ruler

We show that the baryonic oscillations expected in the galaxy power spectrummay be used as a "standard cosmological ruler'' to facilitate accuratemeasurement of the cosmological equation of state. Our approach involves astraight-forward measurement of the oscillation "wavelength'' in Fourier space,which is fixed by fundamental linear physics in the early Universe and hence ishighly model-independent. We quantify the ability of future large-scale galaxyredshift surveys with mean redshifts z~1 and z~3 to delineate the baryonicpeaks in the power spectrum, and derive corresponding constraints on theparameter w describing the equation of state of the dark energy. For example, asurvey of three times the Sloan volume at z ~ 1 can produce a measurement withaccuracy dw ~ 0.1. We suggest that this method of measuring the dark energypowerfully complements other probes such as Type Ia supernovae, and suffersfrom a different (and arguably less serious) set of systematic uncertainties.Comment: Submitted to Astrophysical Journal, 11 pages, 8 figure