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We present an improved method for calculating the parallel and perpendicularvelocity correlation functions directly from peculiar velocity surveys usingweighted maximum-likelihood estimators. A central feature of the new method isthe use of position-dependent weighting scheme that reduces the influence ofnearby galaxies, which are typically overrepresented relative to the moredistant galaxies in most surveys. We demonstrate that the correlation functionscalculated this way are less susceptible to biases due to our particularlocation in the Universe, and thus are more easily comparable to linear theoryand between surveys. Our results suggest that the parallel velocity correlationfunction is a promising cosmological probe, given that it provides a betterapproximation of a Gaussian distribution than other velocity correlationfunctions and that its bias is more easily minimized by weighting. Though theposition weighted parallel velocity correlation function increases thestatistical uncertainty, it decreases the cosmic variance and is expected toprovide more stable and tighter cosmological parameter constraints than othercorrelation methods in conjunction with more precise velocity surveys in thefuture.

Improved Methods for Estimating Peculiar Velocity Correlation Functions Using Volume Weighting