Predicting the peculiar velocities of nearby PSC-z galaxies using the Least Action Principle

Abstract

We use the Least Action Principle to predict the peculiar velocities of PSC-z galaxies inside $cz=2000$\km. Linear theory is used to account for tidal effects to $cz=15000$\km, and we iterate galaxy positions to account for redshift distortions. As the Least Action Principle is valid beyond Linear theory, we can predict reliable peculiar velocities even for very nearby galaxies (ie $cz\le 500$\km). 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 ($\le 10$\mpc) scales; and under the assumption of no biasing, $0.25\le \beta \le 0.75$ (at 90% confidence). We use the reliable predicted peculiar velocities to estimate the Hubble constant \ho from the local volume without ``stepping up'' the distance ladder, finding a confidence range of 65-75\kmM (at 90% confidence).

11 pages, 1 figure. Accepted for publication in MNRAS

References in corpus (8)

• The PSCz Catalogue
• The HST Key Project on the Extragalactic Distance Scale XXVI. The Calibration of Population II Secondary Distance Indicators and the Value of the Hubble Constant
• The Hubble Space Telescope Key Project on the Extragalactic Distance Scale XXIV: The Calibration of Tully-Fisher Relations and the Value of the Hubble Constant
• Cepheid Calibration of the Peak Brightness of SNe Ia -- IX. SN 1989B in NGC 3627
• The Extragalactic Distance Scale Key Project XXVII. A Derivation of the Hubble Constant Using the Fundamental Plane and Dn-Sigma Relations in Leo I, Virgo, and Fornax
• The IRAS PSCz Dipole
• The Hubble Space Telescope Extragalactic Distance Scale Key Project XXIII. The Discovery of Cepheids In NGC 3319
• The HST Key Project on the Extragalactic Distance Scale XVII. The Cepheid Distance to NGC 4725

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• The 1000 Brightest HIPASS Galaxies: Newly Cataloged Galaxies
• Light and Motion in the Local Volume
• Numerical action reconstruction of the dynamical history of dark matter haloes in N-body simulations
• Local Supercluster Dynamics: External Tidal Impact of the PSCz sample traced by Optimized Numerical Least Action Method
• Tracing the environmental history of observed galaxies via extended fast action minimization method