On Density and Velocity Fields and β from the [ITAL]IRAS[/ITAL] PSC[CLC][ITAL]z[/ITAL][/CLC] Survey

Schmoldt, I.; Saar, V.; Saha, Prasenjit; Branchini, E.; Efstathiou, G.; Frenk, Carlos S.; Keeble, Oliver; Maddox, S.; McMahon, R. G.; Oliver, Seb; Rowan-Robinson, M.; Saunders, Will; Sutherland, William J.; Tadros, H.; White, Simon D. M.

doi:10.1086/301001

Cited by 44 publications

(37 citation statements)

References 19 publications

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“…This allows use of the Wiener-type reconstruction methods to derive the true density and velocity fields and to get an independent estimate of the biasing parameter. The first fields to be studied were taken from the 2-Jy survey by Yahil et al ͑1991͒, the last fields came from the PSCz survey by Branchini et al ͑1999͒ andSchmoldt et al ͑1999͒.…”

Section: Iras Redshift Samples: Point Source Catalog Zmentioning

confidence: 99%

Scaling laws in the distribution of galaxies

et al. 2005

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Past surveys have revealed that the large-scale distribution of galaxies in the universe is far from random: it is highly structured over a vast range of scales. Surveys being currently undertaken and being planned for the next decades will provide a wealth of information about this structure. The ultimate goal must be not only to describe galaxy clustering as it is now, but also to explain how this arose as a consequence of evolutionary processes acting on the initial conditions that we see in the cosmic microwave background anisotropy data. In order to achieve this we need to build mathematically quantifiable descriptions of cosmic structure. Identifying where scaling laws apply and the nature of those scaling laws is an important part of understanding which physical mechanisms have been responsible for the organization of clusters of galaxies, superclusters, and the voids between them. Finding where these scaling laws are broken is equally important since this indicates the transition to different underlying physics. In describing scaling laws it is helpful to make analogies with fractals, mathematical constructs that can possess a wide variety of scaling properties. We must beware, however, of saying that the universe is a fractal on some range of scales: it merely exhibits a specific kind of fractal-like behavior on those scales. The richness of fractal scaling behavior is an important supplement to the usual battery of statistical descriptors. This article reviews the history of how we have learned about the structure of the universe and presents the data and methodologies that are relevant to an understanding of any scaling properties that structure may have. The ultimate goal is to have a complete understanding of how that structure emerged. We are getting close! CONTENTS

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Section: Iras Redshift Samples: Point Source Catalog Zmentioning

confidence: 99%

Scaling laws in the distribution of galaxies

et al. 2005

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“…In analogy with the 2-D case, a mask (e.g. to describe the ZOA) can be formulated in the 3-D harmonic formalism (Heavens & Taylor 1995;Schmoldt et al 2000). However, for the simplicity of the analysis, first populated the ZOA with mock galaxies according to the procedure of Yahil et al (1991), and then applied the reconstruction over the full sky.…”

Section: -D Reconstructionmentioning

confidence: 99%

“…However, for the simplicity of the analysis, first populated the ZOA with mock galaxies according to the procedure of Yahil et al (1991), and then applied the reconstruction over the full sky. Webster et al (1997) and Schmoldt et al (2000) extended this analysis and presented detailed maps of the reconstructed fields, as well as optimal determinations of the Local Group dipole and bulk flows. Lahav et al (2000) used Wiener filtering to study the the extent of the Supergalactic Plane.…”

Section: -D Reconstructionmentioning

confidence: 99%

The Universe behind the Milky Way

Kraan-Korteweg

Lahav

2000

Astronomy and Astrophysics Review

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Abstract. Due to the foreground extinction of the Milky Way, galaxies appear increasingly fainter the closer they lie to the Galactic Equator, creating a "zone of avoidance" of about 25% in the distribution of optically visible galaxies. A "whole-sky" map of galaxies is essential, however, for understanding the dynamics in our local Universe, in particular the peculiar velocity of the Local Group with respect to the Cosmic Microwave Background and velocity flow fields such as in the Great Attractor region.Various dynamically important structures behind the Milky Way have only recently been made "visible" through dedicated deep surveys at various wavelengths. The wide range of observational searches (optical, near infrared, far infrared, radio and X-ray) for galaxies in the Zone of Avoidance are reviewed, including a discussion on the limitations and selection effects of these partly complementary approaches. The uncovered and suspected large-scale structures are summarized. Reconstruction methods of the density field in the Zone of Avoidance are described and the resulting predictions compared with observational evidence. The comparison between reconstructed density fields and the observed galaxy distribution allow derivations of the density and biasing parameters Ω 0 and b.

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“…Branchini et al 1999;Schmoldt et al 1999;Valentine et al 2000;Sharpe et al 2001) are free from systematic biases arising from having neglected the large scale contribution from scales beyond its realm. Moreover, since the IRAS PSCz survey is considerably deeper than 100 h −1 Mpc, it is reasonable to assume that the PSCz catalog can be used to predict unbiased velocities well beyond our Local Supercluster that, if compared with observed galaxy peculiar velocities, can discriminate among different cosmologies characterized by different values of Ω m , like the ΛCDM and τCDM models.…”

Section: Discussionmentioning

confidence: 99%

Local supercluster dynamics: external tidal impact of the PSCzsample traced by optimized numerical least action method

Romano-Díaz¹,

Branchini²,

Weygaert³

2005

A&A

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Abstract. We assess the extent to which the flux-limited IRAS PSCz redshift survey encapsulates the complete or major share of matter inhomogeneities responsible for the external tidal forces affecting the peculiar velocity flow within the Local Supercluster and its immediate surroundings. We here investigate this issue on the basis of artificially constructed galaxy catalogs. Two large unconstrained N-body simulations of cosmic structure formation in two different cosmological scenarios form the basis of this study. From these N-body simulations a set of galaxy mock catalogs is selected. From these a variety of datasets is selected imitating the observational conditions of either the local volume-limited Local Supercluster mimicking NBG catalog or the deeper magnitude-limited PSCz catalog. The mildly nonlinear dynamics in the "mock" Local Supercluster and PSCz velocities are analyzed by means of the Least Action Principle technique in its highly optimized implementation of the Fast Action Method. By comparing the velocities in these reconstructions with the "true" velocities of the corresponding galaxy mock catalogs we assess the extent and nature of the external tidal influence on the Local Supercluster volume. We find that the dynamics in the inner 30 h −1 Mpc volume is strongly affected by the external forces. Most of the external forces can be traced back to a depth of no more than 100 h −1 Mpc. This is concluded from the fact that the FAM reconstructions of the 100 h −1 Mpc PSCz volume appear to have included most gravitational influences. In addition, we demonstrate that for all considered cosmological models the bulk flow and shear components of the tidal velocity field generated by the external distribution of PSCz galaxies provides sufficient information for representing the full external tidal force field.

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On Density and Velocity Fields and β from the [ITAL]IRAS[/ITAL] PSC[CLC][ITAL]z[/ITAL][/CLC] Survey

Cited by 44 publications

References 19 publications

Scaling laws in the distribution of galaxies

Scaling laws in the distribution of galaxies

The Universe behind the Milky Way

Local supercluster dynamics: external tidal impact of the PSCzsample traced by optimized numerical least action method

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