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Dark energy perturbations in N-body simulations. / Dakin, Jeppe; Hannestad, Steen; Tram, Thomas; Knabenhans, Mischa; Stadel, Joachim.
In: Journal of Cosmology and Astroparticle Physics, No. 8, 013, 12.08.2019.Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review
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TY - JOUR
T1 - Dark energy perturbations in N-body simulations
AU - Dakin, Jeppe
AU - Hannestad, Steen
AU - Tram, Thomas
AU - Knabenhans, Mischa
AU - Stadel, Joachim
PY - 2019/8/12
Y1 - 2019/8/12
N2 - We present N-body simulations which are fully compatible with general relativity, with dark energy consistently included at both the background and perturbation level. We test our approach for dark energy parameterised as both a fluid, and using the parameterised post-Friedmann (PPF) formalism. In most cases, dark energy is very smooth relative to dark matter so that its leading effect on structure formation is the change to the background expansion rate. This can be easily incorporated into Newtonian N-body simulations by changing the Friedmann equation. However, dark energy perturbations and relativistic corrections can lead to differences relative to Newtonian N-body simulations at the tens of percent level for scales k < (10-3-10-2) Mpc-1, and given the accuracy of upcoming large scale structure surveys such effects must be included. In this paper we will study both effects in detail and highlight the conditions under which they are important. We also show that our N-body simulations exactly reproduce the results of the Boltzmann solver CLASS for all scales which remain linear.
AB - We present N-body simulations which are fully compatible with general relativity, with dark energy consistently included at both the background and perturbation level. We test our approach for dark energy parameterised as both a fluid, and using the parameterised post-Friedmann (PPF) formalism. In most cases, dark energy is very smooth relative to dark matter so that its leading effect on structure formation is the change to the background expansion rate. This can be easily incorporated into Newtonian N-body simulations by changing the Friedmann equation. However, dark energy perturbations and relativistic corrections can lead to differences relative to Newtonian N-body simulations at the tens of percent level for scales k < (10-3-10-2) Mpc-1, and given the accuracy of upcoming large scale structure surveys such effects must be included. In this paper we will study both effects in detail and highlight the conditions under which they are important. We also show that our N-body simulations exactly reproduce the results of the Boltzmann solver CLASS for all scales which remain linear.
KW - cosmological simulations, dark energy theory, dark matter simulations, power spectrum
UR - http://www.scopus.com/inward/record.url?scp=85072131376&partnerID=8YFLogxK
U2 - 10.1088/1475-7516/2019/08/013
DO - 10.1088/1475-7516/2019/08/013
M3 - Journal article
JO - Journal of Cosmology and Astroparticle Physics
JF - Journal of Cosmology and Astroparticle Physics
SN - 1475-7516
IS - 8
M1 - 013
ER -