scholarly journals Perturbation Theory Reloaded: Analytical Calculation of Nonlinearity in Baryonic Oscillations in the Real‐Space Matter Power Spectrum

2006 ◽  
Vol 651 (2) ◽  
pp. 619-626 ◽  
Author(s):  
Donghui Jeong ◽  
Eiichiro Komatsu
Keyword(s):  
Perturbation Theory ◽  
Power Spectrum ◽  
Analytical Calculation ◽  
Real Space ◽  
The Real ◽  
Matter Power Spectrum

scholarly journals Simulations and symmetries

2020 ◽  
Vol 492 (4) ◽  
pp. 5754-5763 ◽  
Author(s):  
Chirag Modi ◽  
Shi-Fan Chen ◽  
Martin White
Keyword(s):  
Perturbation Theory ◽  
Power Spectrum ◽  
Galaxy Formation ◽  
Hybrid Approach ◽  
Limited Range ◽  
Real Space ◽  
Equivalent Model ◽  
The Real ◽  
Body Dynamics ◽  
The Cost

ABSTRACT We investigate the range of applicability of a model for the real-space power spectrum based on N-body dynamics and a (quadratic) Lagrangian bias expansion. This combination uses the highly accurate particle displacements that can be efficiently achieved by modern N-body methods with a symmetries-based bias expansion which describes the clustering of any tracer on large scales. We show that at low redshifts, and for moderately biased tracers, the substitution of N-body-determined dynamics improves over an equivalent model using perturbation theory by more than a factor of two in scale, while at high redshifts and for highly biased tracers the gains are more modest. This hybrid approach lends itself well to emulation. By removing the need to identify haloes and subhaloes, and by not requiring any galaxy-formation-related parameters to be included, the emulation task is significantly simplified at the cost of modelling a more limited range in scale.

scholarly journals Matter power spectrum from a Lagrangian-space regularization of perturbation theory

2013 ◽  
Vol 87 (8) ◽  
Author(s):  
Patrick Valageas ◽  
Takahiro Nishimichi ◽  
Atsushi Taruya
Keyword(s):  
Perturbation Theory ◽  
Power Spectrum ◽  
Matter Power Spectrum

scholarly journals Generating approximate halo catalogues for blind challenges in precision cosmology

2019 ◽  
Vol 485 (2) ◽  
pp. 2407-2416 ◽  
Author(s):  
Lehman H Garrison ◽  
Daniel J Eisenstein
Keyword(s):  
Dark Matter ◽  
Transfer Function ◽  
Power Spectrum ◽  
High Precision ◽  
Real Space ◽  
Dark Matter Halo ◽  
The Real ◽  
The Galaxy ◽  
Similar Accuracy ◽  
Better Than

ABSTRACT We present a method for generating suites of dark matter halo catalogues with only a few N-body simulations, focusing on making small changes to the underlying cosmology of a simulation with high precision. In the context of blind challenges, this allows us to re-use a simulation by giving it a new cosmology after the original cosmology is revealed. Starting with full N-body realizations of an original cosmology and a target cosmology, we fit a transfer function that displaces haloes in the original so that the galaxy/HOD power spectrum matches that of the target cosmology. This measured transfer function can then be applied to a new realization of the original cosmology to create a new realization of the target cosmology. For a 1 per cent change in σ8, we achieve 0.1 per cent accuracy to $k = 1\, h\, \mathrm{Mpc}^{-1}$ in the real-space power spectrum; this degrades to 0.3 per cent when the transfer function is applied to a new realization. We achieve similar accuracy in the redshift-space monopole and quadrupole. In all cases, the result is better than the sample variance of our $1.1\, h^{-1}\, \mathrm{Gpc}$ simulation boxes.

scholarly journals Contributions from primordial non-Gaussianity and general relativity to the galaxy power spectrum

2021 ◽  
Vol 2021 (12) ◽  
pp. 025
Author(s):  
Rebeca Martinez-Carrillo ◽  
Juan Carlos Hidalgo ◽  
Karim A. Malik ◽  
Alkistis Pourtsidou
Keyword(s):  
General Relativity ◽  
Power Spectrum ◽  
Stage Iv ◽  
Real Space ◽  
Order Effects ◽  
Leading Order ◽  
Bias Parameter ◽  
Matter Power Spectrum ◽  
The Galaxy ◽  
The One

Abstract We compute the real space galaxy power spectrum, including the leading order effects of General Relativity and primordial non-Gaussianity from the f NL and g NL parameters. Such contributions come from the one-loop matter power spectrum terms dominant at large scales, and from the factors of the non-linear bias parameter b NL (akin to the Newtonian b ϕ). We assess the detectability of these contributions in Stage-IV surveys. In particular, we note that specific values of the bias parameter may erase the primordial and relativistic contributions to the configuration space power spectrum.

scholarly journals Impact of cosmological signatures in two-point statistics beyond the linear regime

2020 ◽  
Author(s):  
D V Gomez-Navarro ◽  
A J Mead ◽  
A Aviles ◽  
A de la Macorra
Keyword(s):  
Perturbation Theory ◽  
Correlation Function ◽  
Power Spectrum ◽  
Large Scale ◽  
Line Of Sight ◽  
Linear Regime ◽  
Dark Sector ◽  
Linear Evolution ◽  
Matter Power Spectrum ◽  
Small Scales

Abstract Some beyond ΛCDM cosmological models have dark-sector energy densities that suffer phase transitions. Fluctuations entering the horizon during such a transition can receive enhancements that ultimately show up as a distinctive bump in the power spectrum relative to a model with no phase transition. In this work, we study the non-linear evolution of such signatures in the matter power spectrum and correlation function using N-body simulations, perturbation theory and hmcode- a halo-model based method. We focus on modelling the response, computed as the ratio of statistics between a model containing a bump and one without it, rather than in the statistics themselves. Instead of working with a specific theoretical model, we inject a parametric family of Gaussian bumps into otherwise standard ΛCDM spectra. We find that even when the primordial bump is located at linear scales, non-linearities tend to produce a second bump at smaller scales. This effect is understood within the halo model due to a more efficient halo formation. In redshift space these nonlinear signatures are partially erased because of the damping along the line-of-sight direction produced by non-coherent motions of particles at small scales. In configuration space, the bump modulates the correlation function reflecting as oscillations in the response, as it is clear in linear Eulerian theory; however, they become damped because large scale coherent flows have some tendency to occupy regions more depleted of particles. This mechanism is explained within Lagrangian Perturbation Theory and well captured by our simulations.

scholarly journals Spherical harmonic analysis of the PSCz galaxy catalogue: redshift distortions and the real-space power spectrum

1999 ◽  
Vol 305 (3) ◽  
pp. 527-546 ◽  
Author(s):  
H. Tadros ◽  
W. E. Ballinger ◽  
A. N. Taylor ◽  
A. F. Heavens ◽  
G. Efstathiou ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Harmonic Analysis ◽  
Spherical Harmonic ◽  
Real Space ◽  
Spherical Harmonic Analysis ◽  
The Real
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