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We have used the Optical Redshift Survey (ORS; Santiago et al. 1995) to construct the gravity field due to fluctuations in the galaxy density field out to distances of 8000 km/s. At large scales where linear theory applies, the comparison…

In this work we investigate the nonlinear and nonlocal relation between cosmological density and peculiar velocity fields. Our goal is to provide an algorithm for the recon- struction of the nonlinear velocity field from the fully nonlinear…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Francisco-Shu Kitaura , Raul E. Angulo , Yehuda Hoffman , Stefan Gottl"ober

Using the 2MASS near-infrared photometry and high signal-to-noise HI 21-cm data from the Arecibo, Green Bank, Nancay, and Parkes telescopes, we calculate the redshift-independent distances and peculiar velocities of 2,018 bright inclined…

Given a redshift survey of galaxies with measurements of apparent magnitudes, we present a novel method for measuring the growth rate $f(\Omega)$ of cosmological linear perturbations. We use the galaxy distribution within the survey to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Adi Nusser , Enzo Branchini , Marc Davis

We present a cosmography analysis of the Local Universe based on the recently released Two-Micron All-Sky Redshift Survey (2MRS). Our method is based on a Bayesian Networks Machine Learning algorithm (the Kigen-code) which self-consistently…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-08 Francisco-Shu Kitaura , Pirin Erdogdu , Sebastian E. Nuza , Arman Khalatyan , Raul E. Angulo , Yehuda Hoffman , Stefan Gottloeber

We characterize the peculiar velocity field of the local large-scale structure reconstructed from the $2M++$ survey, by treating it as a fluid, extracting the divergence via different approximations over a range pf averaged scales. This…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-22 Erick Pastén , Sebastián Gálvez , Víctor Cárdenas

We create a combined sample of 10,904 late and early-type galaxies from the 2MTF and 6dFGSv surveys in order to accurately measure bulk flow in the local Universe. Galaxies and groups of galaxies common between the two surveys are used to…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-22 Fei Qin , Cullan Howlett , Lister Staveley-Smith , Tao Hong

Cosmological implications of the observed large-scale peculiar velocities are reviewed, alone or combined with redshift surveys and CMB data. The latest version of the POTENT method for reconstructing the underlying three-dimensional…

Astrophysics · Physics 2007-05-23 Avishai Dekel

We present a comparison between the peculiar velocity fields measured from the SFI all-sky Sbc-Sc Tully-Fisher catalog and that derived from the \iras 1.2 Jy redshift survey galaxy distribution. The analysis is based on the expansion of…

We present a simple method for measuring cosmological bulk flows from large redshift surveys, based on the apparent dimming or brightening of galaxies due to their peculiar motion. It is aimed at estimating bulk flows of cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Adi Nusser , Enzo Branchini , Marc Davis

The low-order kinematic moments of galaxies, namely bulk flow and shear, enables us to test whether theoretical models can accurately describe the evolution of the mass density field in the nearby Universe. We use the so-called etaMLE…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-05 Fei Qin , Cullan Howlett , Lister Staveley-Smith , Tao Hong

Full sky surveys of peculiar velocity are arguably the best way to map the large scale structure out to distances of a few times 100 Mpc/h. Using the largest and most accurate ever catalog of galaxy peculiar velocities "Cosmicflows-2", the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-24 Yehuda Hoffman , Helene M. Courtois , R. Brent Tully

We compare the amplitudes of fluctuations probed by the 2dF Galaxy Redshift Survey and by the latest measurements of the Cosmic Microwave Background anisotropies. By combining the 2dFGRS and CMB data we find the linear-theory rms mass…

We present a numerical study of the relation between the cosmic peculiar velocity field and the gravitational acceleration field. We show that on mildly non-linear scales (4-10 Mpc Gaussian smoothing), the distribution of the Cartesian…

Large-scale structure (LSS) and tracer bias connect observable populations to the cosmic matter distribution. While galaxies are standard tracers, transient events such as gravitational-wave sources can also probe LSS despite large…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-25 Yu-Tong Su , Zhengxiang Li

While much of the focus of observational cosmology is on the high redshift universe it is important not to neglect the very local universe as a source of cosmological information. The inner profiles and number counts of low mass halos have…

Astrophysics · Physics 2007-05-23 Karen L. Masters

Measurements of the cosmological density parameter Omega using techniques that exploit the gravity-induced motions of galaxies constrain, in linear perturbation theory, the degenerate parameter combination beta = Omega^{0.6}/b, where the…

Astrophysics · Physics 2011-08-23 Andreas A. Berlind , Vijay K. Narayanan , David H. Weinberg

We present a self consistent nonparametric model of the local cosmic velocity field based on the density distribution in the PSCz redshift survey of IRAS galaxies. The error analysis, carried out on mock PSCz catalogues constructed from…

We only see a small fraction of the matter in the universe, but the rest gives itself away by the impact of its gravity. Peculiar velocities have the potential to be a powerful tool to trace this matter however previous peculiar velocity…

Astrophysics · Physics 2007-08-23 Karen L. Masters

We use the observed abundance and clustering of galaxies from the 2dFGRS to determine the matter density Omega_m and the linear amplitude of mass fluctuations sigma_8. We use a method based on the conditional luminosity function, which…

Astrophysics · Physics 2009-11-07 Frank C. van den Bosch , H. J. Mo , Xiaohu Yang