skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: New approach for precise computation of Lyman-α forest power spectrum with hydrodynamical simulations

Abstract

Current experiments are providing measurements of the flux power spectrum from the Lyman-α forests observed in quasar spectra with unprecedented accuracy. Their interpretation in terms of cosmological constraints requires specific simulations of at least equivalent precision. In this paper, we present a suite of cosmological N-body simulations with cold dark matter and baryons, specifically aiming at modeling the low-density regions of the inter-galactic medium as probed by the Lyman-α forests at high redshift. The simulations were run using the GADGET-3 code and were designed to match the requirements imposed by the quality of the current SDSS-III/BOSS or forthcoming SDSS-IV/eBOSS data. They are made using either 2 × 768{sup 3} ≅ 1 billion or 2 × 192{sup 3} ≅ 14 million particles, spanning volumes ranging from (25 Mpc h{sup −1}){sup 3} for high-resolution simulations to (100 Mpc h{sup −1}){sup 3} for large-volume ones. Using a splicing technique, the resolution is further enhanced to reach the equivalent of simulations with 2 × 3072{sup 3} ≅ 58 billion particles in a (100 Mpc h{sup −1}){sup 3} box size, i.e. a mean mass per gas particle of 1.2 × 10{sup 5}M{sub ⊙} h{sup −1}. We show that the resulting power spectrum is accurate at the 2% level over the full rangemore » from a few Mpc to several tens of Mpc. We explore the effect on the one-dimensional transmitted-flux power spectrum of four cosmological parameters (n{sub s}, σ{sub 8}, Ω{sub m} and H{sub 0}) and two astrophysical parameters (T{sub 0} and γ) that are related to the heating rate of the intergalactic medium. By varying the input parameters around a central model chosen to be in agreement with the latest Planck results, we built a grid of simulations that allows the study of the impact on the flux power spectrum of these six relevant parameters. We improve upon previous studies by not only measuring the effect of each parameter individually, but also probing the impact of the simultaneous variation of each pair of parameters. We thus provide a full second-order expansion, including cross-terms, around our central model. We check the validity of the second-order expansion with independent simulations obtained either with different cosmological parameters or different seeds. Finally, a comparison to the one-dimensional Lyman-α forest power spectrum obtained with BOSS by [1] shows an excellent agreement.« less

Authors:
; ; ; ; ;  [1];  [2];  [3]
  1. CEA, Centre de Saclay, IRFU/SPP, Gif-sur-Yvette, F-91191 France (France)
  2. INAF, Osservatorio Astronomico di Trieste, Via G.B. Tiepolo 11, Trieste, 34131 (Italy)
  3. School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom)
Publication Date:
OSTI Identifier:
22373478
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 07; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; BARYONS; DESIGN; NONLUMINOUS MATTER; QUASARS; RED SHIFT; RESOLUTION; SIMULATION; SPECTRA

Citation Formats

Borde, Arnaud, Palanque-Delabrouille, Nathalie, Rossi, Graziano, Yèche, Christophe, LeGoff, Jean-Marc, Rich, Jim, Viel, Matteo, and Bolton, James S., E-mail: arnaud.borde@cea.fr, E-mail: nathalie.palanque-delabrouille@cea.fr, E-mail: graziano@kias.re.kr, E-mail: matteoviel@gmail.com, E-mail: james.bolton@nottingham.ac.uk, E-mail: christophe.yeche@cea.fr, E-mail: jean-marc.le-goff@cea.fr, E-mail: james.rich@cea.fr. New approach for precise computation of Lyman-α forest power spectrum with hydrodynamical simulations. United States: N. p., 2014. Web. doi:10.1088/1475-7516/2014/07/005.
Borde, Arnaud, Palanque-Delabrouille, Nathalie, Rossi, Graziano, Yèche, Christophe, LeGoff, Jean-Marc, Rich, Jim, Viel, Matteo, & Bolton, James S., E-mail: arnaud.borde@cea.fr, E-mail: nathalie.palanque-delabrouille@cea.fr, E-mail: graziano@kias.re.kr, E-mail: matteoviel@gmail.com, E-mail: james.bolton@nottingham.ac.uk, E-mail: christophe.yeche@cea.fr, E-mail: jean-marc.le-goff@cea.fr, E-mail: james.rich@cea.fr. New approach for precise computation of Lyman-α forest power spectrum with hydrodynamical simulations. United States. doi:10.1088/1475-7516/2014/07/005.
Borde, Arnaud, Palanque-Delabrouille, Nathalie, Rossi, Graziano, Yèche, Christophe, LeGoff, Jean-Marc, Rich, Jim, Viel, Matteo, and Bolton, James S., E-mail: arnaud.borde@cea.fr, E-mail: nathalie.palanque-delabrouille@cea.fr, E-mail: graziano@kias.re.kr, E-mail: matteoviel@gmail.com, E-mail: james.bolton@nottingham.ac.uk, E-mail: christophe.yeche@cea.fr, E-mail: jean-marc.le-goff@cea.fr, E-mail: james.rich@cea.fr. Tue . "New approach for precise computation of Lyman-α forest power spectrum with hydrodynamical simulations". United States. doi:10.1088/1475-7516/2014/07/005.
@article{osti_22373478,
title = {New approach for precise computation of Lyman-α forest power spectrum with hydrodynamical simulations},
author = {Borde, Arnaud and Palanque-Delabrouille, Nathalie and Rossi, Graziano and Yèche, Christophe and LeGoff, Jean-Marc and Rich, Jim and Viel, Matteo and Bolton, James S., E-mail: arnaud.borde@cea.fr, E-mail: nathalie.palanque-delabrouille@cea.fr, E-mail: graziano@kias.re.kr, E-mail: matteoviel@gmail.com, E-mail: james.bolton@nottingham.ac.uk, E-mail: christophe.yeche@cea.fr, E-mail: jean-marc.le-goff@cea.fr, E-mail: james.rich@cea.fr},
abstractNote = {Current experiments are providing measurements of the flux power spectrum from the Lyman-α forests observed in quasar spectra with unprecedented accuracy. Their interpretation in terms of cosmological constraints requires specific simulations of at least equivalent precision. In this paper, we present a suite of cosmological N-body simulations with cold dark matter and baryons, specifically aiming at modeling the low-density regions of the inter-galactic medium as probed by the Lyman-α forests at high redshift. The simulations were run using the GADGET-3 code and were designed to match the requirements imposed by the quality of the current SDSS-III/BOSS or forthcoming SDSS-IV/eBOSS data. They are made using either 2 × 768{sup 3} ≅ 1 billion or 2 × 192{sup 3} ≅ 14 million particles, spanning volumes ranging from (25 Mpc h{sup −1}){sup 3} for high-resolution simulations to (100 Mpc h{sup −1}){sup 3} for large-volume ones. Using a splicing technique, the resolution is further enhanced to reach the equivalent of simulations with 2 × 3072{sup 3} ≅ 58 billion particles in a (100 Mpc h{sup −1}){sup 3} box size, i.e. a mean mass per gas particle of 1.2 × 10{sup 5}M{sub ⊙} h{sup −1}. We show that the resulting power spectrum is accurate at the 2% level over the full range from a few Mpc to several tens of Mpc. We explore the effect on the one-dimensional transmitted-flux power spectrum of four cosmological parameters (n{sub s}, σ{sub 8}, Ω{sub m} and H{sub 0}) and two astrophysical parameters (T{sub 0} and γ) that are related to the heating rate of the intergalactic medium. By varying the input parameters around a central model chosen to be in agreement with the latest Planck results, we built a grid of simulations that allows the study of the impact on the flux power spectrum of these six relevant parameters. We improve upon previous studies by not only measuring the effect of each parameter individually, but also probing the impact of the simultaneous variation of each pair of parameters. We thus provide a full second-order expansion, including cross-terms, around our central model. We check the validity of the second-order expansion with independent simulations obtained either with different cosmological parameters or different seeds. Finally, a comparison to the one-dimensional Lyman-α forest power spectrum obtained with BOSS by [1] shows an excellent agreement.},
doi = {10.1088/1475-7516/2014/07/005},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 07,
volume = 2014,
place = {United States},
year = {Tue Jul 01 00:00:00 EDT 2014},
month = {Tue Jul 01 00:00:00 EDT 2014}
}