505 results on '"Redshift-Space Distortions"'
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502. Effects of Evolution on the Diameter-Redshift Relation
- Author
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Beatrice M. Tinsley
- Subjects
Redshift-space distortions ,Physics ,Space and Planetary Science ,Radio galaxy ,Galaxy formation and evolution ,Elliptical galaxy ,Astronomy ,Astronomy and Astrophysics ,Quasar ,Astrophysics ,Galaxy ,Redshift ,Cosmology - Published
- 1972
503. Properties of the redshift-magnitude bands in the Coma cluster
- Author
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W. G. Tifft
- Subjects
Redshift-space distortions ,Physics ,Space and Planetary Science ,Magnitude (astronomy) ,Coma Cluster ,Astronomy ,Astronomy and Astrophysics ,Quasar ,Astrophysics ,Brightest cluster galaxy ,Galaxy cluster ,Redshift ,Luminosity - Published
- 1973
504. Distribution function approach to redshift space distortions, Part III: halos and galaxies
- Author
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Vincent Desjacques, Uroš Seljak, Teppei Okumura, University of Zurich, and Okumura, Teppei
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,530 Physics ,Dark matter ,FOS: Physical sciences ,ddc:500.2 ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Power spectrum ,Redshift-space distortions ,Velocity Moments ,0103 physical sciences ,Galaxy clustering ,010303 astronomy & astrophysics ,Redshift surveys ,Physics ,010308 nuclear & particles physics ,Spectral density ,Velocity dispersion ,Astronomy and Astrophysics ,Galaxy ,Redshift ,Distribution function ,10231 Institute for Computational Science ,3103 Astronomy and Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
It was recently shown that the power spectrum in redshift space can be written as a sum of cross-power spectra between number weighted velocity moments. We investigate the properties of these power spectra for simulated galaxies and dark matter halos and compare them to the dark matter power spectra, generalizing the concept of the bias. Because all of the quantities are number weighted this approach is well defined even for sparse systems such as massive halos, in contrasts to the previous approaches to RSD where velocity correlations have been explored. We find that the number density weighting leads to a strong scale dependence of the bias terms for momentum density auto-correlation and cross-correlation with density. This trend becomes more significant for the more biased halos and leads to an enhancement of RSD power relative to the linear theory. Fingers-of-god effects, which in this formalism come from the correlations of the higher order moments beyond the momentum density, lead to smoothing of the power spectrum and can reduce this enhancement of power, but are relatively small for halos with no small-scale velocity dispersion. In comparison, for a more realistic galaxy sample with satellites the velocity dispersion generated by satellite motions inside the halos leads to a larger power suppression on small scales, but this depends on the satellite fraction. We investigate several statistics such as the two-dimensional power spectrum, its multipole moments, its powers of mu^2, and configuration space statistics. Overall we find that the nonlinear effects in realistic galaxy samples such as luminous red galaxies affect the redshift space clustering on very large scales: for example, the quadrupole moment is affected by 10% for k, 28 pages, 12 figures
505. Towards testing the theory of gravity with DESI: summary statistics, model predictions and future simulation requirements
- Author
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Cristiano G. Sabiu, Shadab Alam, S. Fromenteau, Vitali Halenka, Mustapha Ishak, Hans A. Winther, Yi Zheng, Yan-Chuan Cai, Alejandro Aviles, Alma X. Gonzalez-Morales, Pierros Ntelis, Mariana Vargas-Magaña, César Hernández-Aguayo, Wojciech A. Hellwing, Jennifer Menesses Rizo, Baojiu Li, Marius Cautun, Alexander Eggemeier, Jian-hua He, Georgios Valogiannis, N. Chandrachani Devi, Jorge L. Cervantes-Cota, Christopher J. Miller, Kazuya Koyama, Axel de la Macorra, Gustavo Niz, Matias Rodriguez Otero, Carolina Cuesta-Lazaro, Christian Arnold, Pauline Zarrouk, Zachary Slepian, Eva-Maria Mueller, Alejo Stark, Gong-Bo Zhao, Octavio Valenzuela, Rachel Bean, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
chameleon ,cosmological model ,Modified gravity ,constraint ,higher-order ,gravitation: model ,media_common.quotation_subject ,Astrophysics - cosmology and nongalactic astrophysics ,Dark matter ,Observable universe ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Cosmological simulations ,01 natural sciences ,Cosmology ,weak field ,dark matter ,membrane model ,Gravitation ,Redshift-space distortions ,estimator ,DESI ,gravitation: lens ,0103 physical sciences ,general relativity ,Galaxy clustering ,Statistical physics ,dark energy ,010303 astronomy & astrophysics ,Weak gravitational lensing ,media_common ,Physics ,Redshift surveys ,010308 nuclear & particles physics ,two-point function ,Astronomy and Astrophysics ,solar system ,redshift ,Universe ,gravitation: f(R) ,statistics ,black hole: coalescence ,Dark energy ,many-body problem ,galaxy ,expansion: acceleration ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,statistical - Abstract
Shortly after its discovery, General Relativity (GR) was applied to predict the behavior of our Universe on the largest scales, and later became the foundation of modern cosmology. Its validity has been verified on a range of scales and environments from the Solar system to merging black holes. However, experimental confirmations of GR on cosmological scales have so far lacked the accuracy one would hope for — its applications on those scales being largely based on extrapolation and its validity there sometimes questioned in the shadow of the discovery of the unexpected cosmic acceleration. Future astronomical instruments surveying the distribution and evolution of galaxies over substantial portions of the observable Universe, such as the Dark Energy Spectroscopic Instrument (DESI), will be able to measure the fingerprints of gravity and their statistical power will allow strong constraints on alternatives to GR. In this paper, based on a set of N-body simulations and mock galaxy catalogs, we study the predictions of a number of traditional and novel summary statistics beyond linear redshift distortions in two well-studied modified gravity models — chameleon f(R) gravity and a braneworld model — and the potential of testing these deviations from GR using DESI. These summary statistics employ a wide array of statistical properties of the galaxy and the underlying dark matter field, including two-point and higher-order statistics, environmental dependence, redshift space distortions and weak lensing. We find that they hold promising power for testing GR to unprecedented precision. The major future challenge is to make realistic, simulation-based mock galaxy catalogs for both GR and alternative models to fully exploit the statistic power of the DESI survey (by matching the volumes and galaxy number densities of the mocks to those in the real survey) and to better understand the impact of key systematic effects. Using these, we identify future simulation and analysis needs for gravity tests using DESI.
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