Geometric and dynamic distortions in anisotropic galaxy clustering

Blazek, Jonathan; Seljak, Uroš; Vlah, Zvonimir; Okumura, Teppei

doi:10.1088/1475-7516/2014/04/001

Cited by 18 publications

(19 citation statements)

References 112 publications

(216 reference statements)

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“…For instance, Refs. [66,67] find that they need to introduce two different second-order bias parameters for the halo density-density, b 00 2 and for the halo density-momentum, b 01 2 to explain the simulated halo power spectrum. As is already discussed in [66], the difference can be, at least qualitatively, explained by the b 3nl term.…”

Section: Summary and Discussionmentioning

confidence: 99%

“…An advantage of the momentum spectrum is that it can be easily measured from N -body simulations without any ambiguity in interpolating the velocity divergence field [64]. Also, since the momentum spectrum is an essential ingredient in predicting the nonlinear RSDs (see [62][63][64][65][66][67]), it would be important to see an impact of the nonlocal bias terms on the momentum spectrum. Here we derive an explicit formula including the nonlocal bias terms up to third order and show that it can be renormalized in a similar manner to the case of halo and matter density correlation.…”

Section: The Halo-matter Cross Statistics In the Presence Of Nonlmentioning

confidence: 99%

“…-61]. We also investigate the cross spectrum between halo density and matter momentum which was recently studied in modeling the RSDs in the Distribution Function approach (see [62][63][64][65][66][67] for a series of papers) and should be simultaneously explained by the same bias values if the model works.…”

Section: Introductionmentioning

confidence: 99%

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Understanding higher-order nonlocal halo bias at large scales by combining the power spectrum with the bispectrum

et al. 2014

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Understanding the relation between underlying matter distribution and biased tracers such as galaxies or dark matter halos is essential to extract cosmological information from ongoing or future galaxy redshift surveys. At sufficiently large scales such as the Baryon Acoustic Oscillation (BAO) scale, a standard approach for the bias problem on the basis of the perturbation theory (PT) is to assume the 'local bias' model in which the density field of biased tracers is deterministically expanded in terms of matter density field at the same position. The higher-order bias parameters are then determined by combining the power spectrum with higher-order statistics such as the bispectrum.As is pointed out by recent studies, however, nonlinear gravitational evolution naturally induces nonlocal bias terms even if initially starting only with purely local bias. As a matter of fact, previous works showed that the second-order nonlocal bias term, which corresponds to the gravitational tidal field, is important to explain the characteristic scale-dependence of the bispectrum. In this paper we extend the nonlocal bias term up to third order, and investigate whether the PT-based model including nonlocal bias terms can simultaneously explain the power spectrum and the bispectrum of simulated halos in N -body simulations. The bias renormalization procedure ensures that only one additional term is necessary to be introduced to the power spectrum as a next-to-leading order correction, even if third-order nonlocal bias terms are taken into account. We show that the power spectrum, including density and momentum, and the bispectrum between halo and matter in Nbody simulations can be simultaneously well explained by the model including up to third-order nonlocal bias terms at k < ∼ 0.1h/Mpc. Also, the results are in a good agreement with theoretical predictions of a simple coevolution picture, although the agreement is not perfect. These trend can be found for a wide range of halo mass, 0.7 < ∼ M halo [10 13 M⊙/h] < ∼ 20 at various redshifts, 0 ≤ z ≤ 1. These demonstrations clearly show a failure of the local bias model even at such large scales, and we conclude that nonlocal bias terms should be consistently included in order to accurately model statistics of halos.

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Section: Summary and Discussionmentioning

confidence: 99%

Section: The Halo-matter Cross Statistics In the Presence Of Nonlmentioning

confidence: 99%

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Understanding higher-order nonlocal halo bias at large scales by combining the power spectrum with the bispectrum

et al. 2014

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“…If the assumed parameter is incorrect, geometric anisotropy is induced to the clustering pattern, known as the AlcockPaczynski (AP) effect (Alcock & Paczynski 1979). The AP distortion alters the radial and transverse distances, thus are sensitive to the Hubble parameter H(z) and the angular-diameter distance DA(z) and known to degenerate with f (z) from the RSD anisotropy (Ballinger et al 1996;Matsubara & Suto 1996;Seo & Eisenstein 2003;Blazek et al 2014).…”

Section: Alcock-paczynski Effectmentioning

confidence: 99%

The Subaru FMOS galaxy redshift survey (FastSound). IV. New constraint on gravity theory from redshift space distortions atz∼ 1.4

Okumura

Hikage

Totani

et al. 2016

Publications of the Astronomical Society of Japan

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209

103

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We measure the redshift-space correlation function from a spectroscopic sample of 2783 emission line galaxies from the FastSound survey. The survey, which uses the Subaru Telescope and covers the redshift ranges of 1.19 < z < 1.55, is the first cosmological study at such high redshifts. We detect clear anisotropy due to redshift-space distortions (RSD) both in the correlation function as a function of separations parallel and perpendicular to the line of sight and its quadrupole moment. RSD has been extensively used to test general relativity on cosmological scales at z < 1. Adopting a ΛCDM cosmology with the fixed expansion history and no velocity dispersion σ v = 0, and using the RSD measurements on scales above 8 h −1 Mpc, we obtain the first constraint on the growth rate at the redshift, f (z)σ 8 (z) = 0.482 ± 0.116 at z ∼ 1.4 after marginalizing over the galaxy bias parameter b(z)σ 8 (z). This corresponds to 4.2σ detection of RSD. Our constraint is consistent with the prediction of general relativity f σ 8 ∼ 0.392 within the 1 − σ confidence level. When we allow σ v to vary and marginalize it over, the growth rate constraint becomes f σ 8 = 0.494−0.120 . We also demonstrate that by combining with the lowz constraints on f σ 8 , high-z galaxy surveys like the FastSound can be useful to distinguish modified gravity models without relying on CMB anisotropy experiments.

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“…Nonlinearity in the power spectrum can be modeled using perturbation theory (PT) [19] and numerical simulations [20,21]. The nonlinearity of RSD was first modeled for dark matter [22][23][24][25][26][27][28][29][30], and the formalisms have been extended to dark matter halos [31][32][33][34][35][36][37][38][39]. Although detailed studies are required to fully understand halo bias [40][41][42][43], the theoretical models for the redshift-space power spectrum of halos were shown to work well up to reasonably small scales.…”

Section: Introductionmentioning

confidence: 99%

Galaxy power spectrum in redshift space: Combining perturbation theory with the halo model

Okumura

Hand²,

Seljak

et al. 2015

Phys. Rev. D

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Theoretical modeling of the redshift-space power spectrum of galaxies is crucially important to correctly extract cosmological information from galaxy redshift surveys. The task is complicated by the nonlinear biasing and redshift space distortion (RSD) effects, which change with halo mass, and by the wide distribution of halo masses and their occupations by galaxies. One of the main modeling challenges is the existence of satellite galaxies that have both radial distribution inside the halos and large virial velocities inside halos, a phenomenon known as the Finger-of-God (FoG) effect. We present a model for the redshift-space power spectrum of galaxies in which we decompose a given galaxy sample into central and satellite galaxies and relate different contributions to the power spectrum to 1-halo and 2-halo terms in a halo model. Our primary goal is to ensure that any parameters that we introduce have physically meaningful values, and are not just fitting parameters. For the lowest order 2-halo terms we use the previously developed RSD modeling of halos in the context of distribution function and perturbation theory approach. This term needs to be multiplied by the effect of radial distances and velocities of satellites inside the halo. To this one needs to add the 1-halo terms, which are non-perturbative. We show that the real space 1-halo terms can be modeled as almost constant, with the finite extent of the satellites inside the halo inducing a small k 2 R 2 term over the range of scales of interest, where R is related to the size of the halo given by its halo mass. We adopt a similar model for FoG in redshift space, ensuring that FoG velocity dispersion is related to the halo mass. For FoG k 2 type expansions do not work over the range of scales of interest and FoG resummation must be used instead. We test several simple damping functions to model the velocity dispersion FoG effect. Applying the formalism to mock galaxies modeled after the "CMASS" sample of the BOSS survey, we find that our predictions for the redshift-space power spectra are accurate up to k ≃ 0.4 h Mpc −1 within 1% if the halo power spectrum is measured using N -body simulations and within 3% if it is modeled using perturbation theory.

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Geometric and dynamic distortions in anisotropic galaxy clustering

Cited by 18 publications

References 112 publications

Understanding higher-order nonlocal halo bias at large scales by combining the power spectrum with the bispectrum

Understanding higher-order nonlocal halo bias at large scales by combining the power spectrum with the bispectrum

The Subaru FMOS galaxy redshift survey (FastSound). IV. New constraint on gravity theory from redshift space distortions atz∼ 1.4

Galaxy power spectrum in redshift space: Combining perturbation theory with the halo model

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