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Full-Text Articles in Physical Sciences and Mathematics
Large-Scale Power Spectrum And Structures From The Enear Galaxy Peculiar Velocity Catalogue, S. Zaroubi, M. Bernardi, L. N. Da Costa, Y. Hoffman, M. V. Alonso, G. Wegner
Large-Scale Power Spectrum And Structures From The Enear Galaxy Peculiar Velocity Catalogue, S. Zaroubi, M. Bernardi, L. N. Da Costa, Y. Hoffman, M. V. Alonso, G. Wegner
Dartmouth Scholarship
We estimate the mass density fluctuations power spectrum (PS) on large scales by applying a maximum likelihood technique to the peculiar velocity data of the recently completed redshift—distance survey of early-type galaxies (hereafter ENEAR). Parametric cold dark matter (CDM)-like models for the PS are assumed, and the best-fitting parameters are determined by maximizing the probability of the model given the measured peculiar velocities of the galaxies, their distances and estimated errors. The method has been applied to CDM models with and without COBE normalization. The general results are in agreement with the high-amplitude power spectra found from similar analyses of …
Noise-Driven Evolution In Stellar Systems - Ii. A Universal Halo Profile, Md Weinberg
Noise-Driven Evolution In Stellar Systems - Ii. A Universal Halo Profile, Md Weinberg
Astronomy Department Faculty Publication Series
Disc instabilities such as arm and bar formation, minor mergers and tidal encounters drive a galaxy from equilibrium. Using the theory that describes the evolution of a galaxy halo as a result of stochastic fluctuations developed in the companion paper to this one, we show that this sort of noise evolves a halo toward a standard profile, independent of its initial profile and concentration. This process can substantially redistribute the mass in dark-matter haloes in the 10 Gyr since formation. Three different noise processes are studied: (i) a bombardment by blobs of mass that are small compared to the halo …
Comparison Of The Enear Peculiar Velocities With The Pscz Gravity Field, A Nusser, L. N. Da Costa, E Branchini, M. Bernardi, M V. Alonso, G Wegner
Comparison Of The Enear Peculiar Velocities With The Pscz Gravity Field, A Nusser, L. N. Da Costa, E Branchini, M. Bernardi, M V. Alonso, G Wegner
Dartmouth Scholarship
We present a comparison between the peculiar velocity field measured from the ENEAR all-sky Dn−σ catalogue and that derived from the galaxy distribution of the IRAS Point Source Catalog Redshift Survey (PSCz). The analysis is based on a modal expansion of these data in redshift space by means of spherical harmonics and Bessel functions. The effective smoothing scale of the expansion is almost linear with redshift reaching 1500kms−1 at 3000kms−1. The general flow patterns in the filtered ENEAR and PSCz velocity fields agree well within 6000kms−1, assuming a linear biasing relation between the mass and …
Noise-Driven Evolution In Stellar Systems - I. Theory, Md Weinberg
Noise-Driven Evolution In Stellar Systems - I. Theory, Md Weinberg
Astronomy Department Faculty Publication Series
We present a theory for describing the evolution of a galaxy caused by stochastic events such as weak mergers, transient spiral structure, orbiting blobs, etc. This noise excites large-scale patterns that drive the evolution of the galactic density profile. In a dark matter halo, the repeated stochastic perturbations preferentially ring the lowest-order modes with only a very weak dependence on the details of their source. The subsequent redistribution of halo mass is determined only by the mechanics of these modes. The halo profile then evolves toward a universal asymptotic form for a wide variety of noise sources. Such a convergence …