High-performance P3M N-body code: CUBEP3M

Harnois-Déraps, Joachim; Pen, Ue-Li; Iliev, Ilian T.; Merz, Hugh; Emberson, J. D.; Desjacques, Vincent

doi:10.1093/mnras/stt1591

Cited by 155 publications

(118 citation statements)

References 71 publications

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“…To test the performance of the reconstruction algorithm, we run a N -body simulation with the CUBEP 3 M code [20]. The simulation involves 2048 3 dark matter particles in a box of length 600 Mpc/h per side.…”

Section: Implementation and Resultsmentioning

confidence: 99%

“…To prevent excessive compression and the associated computational cost, we choose ξ m ≈ 1/10 in the reconstruction. Next we set v m = (5,10,20) and keep ξ m = 1/10 and apply reconstruction to the nonlinear density field. Figure 7 shows the cross-correlation coefficients of the reconstructed density field with the linear initial conditions for different values of the expansion volume limit.…”

Section: Appendix B: Convergence Testsmentioning

confidence: 99%

See 1 more Smart Citation

Nonlinear reconstruction

Zhu

Pen

et al. 2017

Phys. Rev. D

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We present a direct approach to nonparametrically reconstruct the linear density field from an observed nonlinear map. We solve for the unique displacement potential consistent with the nonlinear density and positive definite coordinate transformation using a multigrid algorithm. We show that we recover the linear initial conditions up to the nonlinear scale (r δr δ L > 0.5 for k 1 h/Mpc) with minimal computational cost. This reconstruction approach generalizes the linear displacement theory to fully nonlinear fields, potentially substantially expanding the baryon acoustic oscillations and redshift space distortions information content of dense large scale structure surveys, including for example SDSS main sample and 21cm intensity mapping initiatives.

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Section: Implementation and Resultsmentioning

confidence: 99%

Section: Appendix B: Convergence Testsmentioning

confidence: 99%

Nonlinear reconstruction

Zhu

Pen

et al. 2017

Phys. Rev. D

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“…The cosmic structures underlying our simulations are based on a high-resolution N -body simulation using the CUBEP 3 M code (Harnois-Déraps et al 2013). A 2-level particle-mesh is used to calculate the long-range gravitational forces, kernel-matched to local, direct and exact particle-particle interactions.…”

Section: N -Body Simulationsmentioning

confidence: 99%

Simulating the impact of X-ray heating during the cosmic dawn

Ross

Dixon

Iliev

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Upcoming observations of the 21-cm signal from the Epoch of Reionization will soon provide the first direct detection of this era. This signal is influenced by many astrophysical effects, including long range X-ray heating of the intergalactic gas. During the preceding Cosmic Dawn era the impact of this heating on the 21-cm signal is particularly prominent, especially before spin temperature saturation. We present the largest-volume (349 Mpc comoving=244 h −1 Mpc) full numerical radiative transfer simulations to date of this epoch that include the effects of helium and multi-frequency heating, both with and without X-ray sources. We show that X-ray sources contribute significantly to early heating of the neutral intergalactic medium and, hence, to the corresponding 21-cm signal. The inclusion of hard, energetic radiation yields an earlier, extended transition from absorption to emission compared to the stellar-only case. The presence of X-ray sources decreases the absolute value of the mean 21-cm differential brightness temperature. These hard sources also significantly increase the 21-cm fluctuations compared the common assumption of temperature saturation. The 21-cm differential brightness temperature power spectrum is initially boosted on large scales, before decreasing on all scales. Compared to the case of the cold, unheated intergalactic medium, the signal has lower rms fluctuations and increased non-Gaussianity, as measured by the skewness and kurtosis of the 21-cm probability distribution functions. Images of the 21-cm signal with resolution around 11 arcmin still show fluctuations well above the expected noise for deep integrations with the SKA1-Low, indicating that direct imaging of the X-ray heating epoch could be feasible.

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“…The N -body simulations were carried out as part of the PRACE4LOFAR project (PRACE projects 2012061089 and 2014102339) with the cubep 3 m code (Harnois-Déraps et al 2013), which is based on the older code pmfast (Merz, Pen & Trac 2005). Gravitational forces are calculated on a particle-particle basis at close distances, and on a mesh for longer distances.…”

Section: N -Body Simulationsmentioning

confidence: 99%

Effects of the sources of reionization on 21-cm redshift-space distortions

Majumdar¹,

Jensen²,

Mellema³

et al. 2015

Mon. Not. R. Astron. Soc.

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The observed 21-cm signal from the epoch of reionization will be distorted along the line-of-sight by the peculiar velocities of matter particles. These redshift-space distortions will affect the contrast in the signal and will also make it anisotropic. This anisotropy contains information about the cross-correlation between the matter density field and the neutral hydrogen field, and could thus potentially be used to extract information about the sources of reionization. In this paper, we study a collection of simulated reionization scenarios assuming different models for the sources of reionization. We show that the 21-cm anisotropy is best measured by the quadrupole moment of the power spectrum. We find that, unless the properties of the reionization sources are extreme in some way, the quadrupole moment evolves very predictably as a function of global neutral fraction. This predictability implies that redshift-space distortions are not a very sensitive tool for distinguishing between reionization sources. However, the quadrupole moment can be used as a model-independent probe for constraining the reionization history. We show that such measurements can be done to some extent by first-generation instruments such as LOFAR, while the SKA should be able to measure the reionization history using the quadrupole moment of the power spectrum to great accuracy.

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High-performance P3M N-body code: CUBEP3M

Cited by 155 publications

References 71 publications

Nonlinear reconstruction

Nonlinear reconstruction

Simulating the impact of X-ray heating during the cosmic dawn

Effects of the sources of reionization on 21-cm redshift-space distortions

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