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Paper: Predicting the peculiar velocities of nearby galaxies
Volume: 176, Observational Cosmology: The Development of Galaxy Systems
Page: 280
Authors: Sharpe, Jacob; Rowan-Robinson, Michael; Canavezes, A.; Saunders, W.; Efstathiou, G.; Frenk, C.; Keeble, O.; McMahon, R. G.; Maddox, S.; Oliver, S. J.; Sutherland, W.; Tadros, H.; White, S. D. M.
Abstract: We use the Least Action Principle to predict the peculiar velocities of PSC-z galaxies inside (cz = 2000 kms^{-1}). Linear theory is used to account for tidal effects to (cz = 15000 kms^{-1}), and we iterate galaxy positions to account for redshift distortions. As the Least Action Principle is valid beyond Linear theory, we can predict reliable velocities even for very nearby galaxies (ie cz <= 500 kms^{-1}). These predicted peculiar velocities are then compared with the observed velocities of 12 galaxies with Cepheid distances. The combination of the PSC-z galaxy survey (with its large sky coverage and uniform selection), with the accurate Cepheid distances, makes this comparison relatively free from systematic effects. We find that galaxies are good tracers of the mass, even at small (<= 10 h^{-1}Mpc) scales; and under the assumption of no biasing, β <= 0.75 (at 90% confidence). We use the reliable predicted peculiar velocities to estimate (H0) from the local volume without ``stepping up'' the distance ladder, finding a confidence range of 65-75 kms^{-1}Mpc^{-1} (at 90% confidence).
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