Large-scale bias and the peak background split

Sheth, Ravi K.; Tormen, Giuseppe

doi:10.1046/j.1365-8711.1999.02692.x

Cited by 2,646 publications

(3,829 citation statements)

References 24 publications

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“…Since the rapidly changing force field in dense regions will be mainly calculated as a tree correction, the PM part of the potential can be held fixed or extrapolated over the largest system time step. Since all near range forces are localized to particles in the algorithm only trees in the densest regions need to be updated at smaller fine-grained timesteps while remaining trees can be repaired using methods described by Springel et al (2001). Furthermore, the communication needs will be small at the fine-grained timesteps since forces are all determined locally and few particles will cross domain boundaries.…”

Section: Resultsmentioning

confidence: 99%

“…The boundaries of these domains are determined iteratively using the number of tree force interactions from the last step. It is a one-dimensional version of the orthogonal recursive bisection (ORB) domain decomposition method described in Dubinski (1996) and used in other parallel tree codes like GADGET (Springel et al 2001). At the end of this step, each processor contains a list of particles which requires the same amount of computation to determine tree force corrections.…”

Section: Slice Domain Decompositionmentioning

confidence: 99%

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GOTPM: a parallel hybrid particle-mesh treecode

et al. 2004

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We describe a parallel, cosmological N-body code based on a hybrid scheme using the particle-mesh (PM) and Barnes-Hut (BH) oct-tree algorithm. We call the algorithm GOTPM for Grid-of-Oct-Trees-Particle-Mesh. The code is parallelized using the Message Passing Interface (MPI) library and is optimized to run on Beowulf clusters as well as symmetric multi-processors. The gravitational potential is determined on a mesh using a standard PM method with particle forces determined through interpolation. The softened PM force is corrected for short range interactions using a grid of localized BH trees throughout the entire simulation volume in a completely analogous way to P 3 M methods. This method makes no assumptions about the local density for short range force corrections and so is consistent with the results of the P 3 M method in the limit that the treecode opening angle parameter, θ → 0.The PM method is parallelized using one-dimensional slice domain decomposition. Particles are distributed in slices of equal width to allow mass assignment onto mesh points. The Fourier transforms in the PM method are done in parallel using the MPI implementation of the FFTW package. Parallelization for the tree force corrections is achieved again using one-dimensional slices but the width of each slice is allowed to vary according to the amount of computational work required by the particles within each slice to achieve load balance. The tree force corrections dominate the computational load and so imbalances in the PM density assignment step do not impact the overall load balance and performance significantly. The code performance scales well to 128 processors and is significantly better than competing methods. We present preliminary results from simulations run on different platforms containing up to N = 1G particles to verify the code.

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Section: Resultsmentioning

confidence: 99%

Section: Slice Domain Decompositionmentioning

confidence: 99%

GOTPM: a parallel hybrid particle-mesh treecode

et al. 2004

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“…(Different halo mass definitions lead to different coefficients.) A similar functional form was justified on analytic grounds by Sheth and Tormen (1999), following a chain of argument that ultimately traces back to Press and Schechter (1974) and Bond et al (1991). Discussions of the halo population frequently refer to the characteristic mass scale M * , defined by σ(M * ) = δ c = 1.686,…”

Section: Cmb Anisotropies and Large Scale Structurementioning

confidence: 99%

Observational probes of cosmic acceleration

et al. 2013

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The accelerating expansion of the universe is the most surprising cosmological discovery in many decades, implying that the universe is dominated by some form of "dark energy" with exotic physical properties, or that Einstein's theory of gravity breaks down on cosmological scales. The profound implications of cosmic acceleration have inspired ambitious efforts to understand its origin, with experiments that aim to measure the history of expansion and growth of structure with percent-level precision or higher. We review in detail the four most well established methods for making such measurements: Type Ia supernovae, baryon acoustic oscillations (BAO), weak gravitational lensing, and the abundance of galaxy clusters. We pay particular attention to the systematic uncertainties in these techniques and to strategies for controlling them at the level needed to exploit "Stage IV" dark energy facilities such as BigBOSS, LSST, Euclid, and WFIRST. We briefly review a number of other approaches including redshift-space distortions, the Alcock-Paczynski effect, and direct measurements of the Hubble constant H 0 . We present extensive forecasts for constraints on the dark energy equation of state and parameterized deviations from General Relativity, achievable with Stage III and Stage IV experimental programs that incorporate supernovae, BAO, weak lensing, and cosmic microwave background data. We also show the level of precision required for clusters or other methods to provide constraints competitive with those of these fiducial programs. We emphasize the value of a balanced program that employs several of the most powerful methods in combination, both to cross-check systematic uncertainties and to take advantage of complementary information. Surveys to probe cosmic acceleration produce data sets that support a wide range of scientific investigations, and they continue the longstanding astronomical tradition of mapping the universe in ever greater detail over ever larger scales.

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“…where we use the Sheth & Tormen (1999) HMF and calibrate at z ∼ 5 using the Bouwens et al (2015b) LF. We calibrate over the halo mass range 10 7 − 10 14 M , and therefore extrapolate the LF over M uv = −7.5 to M uv = −24.5 to perform the abundance matching.…”

Section: Calibrationmentioning

confidence: 99%

The Galaxy UV Luminosity Function Before the Epoch of Reionization

Mason

Trenti²,

Treu

2015

Proc. IAU

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We present a model for the evolution of the galaxy ultraviolet (UV) luminosity function (LF) across cosmic time where star formation is linked to the assembly of dark matter halos under the assumption of a mass dependent, but redshift independent, efficiency. We introduce a new self-consistent treatment of the halo star formation history, which allows us to make predictions at z > 10 (lookback time ∼ < 500 Myr), when growth is rapid. With a calibration at a single redshift to set the stellar-to-halo mass ratio, and no further degrees of freedom, our model captures the evolution of the UV LF over all available observations (0 ∼ < z ∼ < 10). The significant drop in luminosity density of currently detectable galaxies beyond z ∼ 8 is explained by a shift of star formation toward less massive, fainter galaxies. Assuming that star formation proceeds down to atomic cooling halos, we derive a reionization optical depth τ = 0.056 +0.007 −0.010 , fully consistent with the latest Planck measurement, implying that the universe is fully reionized at z = 7.84 +0.65 −0.98 . In addition, our model naturally produces smoothly rising star formation histories for galaxies with L ∼ < L * in agreement with observations and hydrodynamical simulations. Before the epoch of reionization at z > 10 we predict the LF to remain well-described by a Schechter function, but with an increasingly steep faint-end slope (α ∼ −3.5 at z ∼ 16). Finally, we construct forecasts for surveys with JWST and WFIRST and predict that galaxies out to z ∼ 14 will be observed. Galaxies at z > 15 will likely be accessible to JWST and WFIRST only through the assistance of strong lensing magnification.

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Large-scale bias and the peak background split

Cited by 2,646 publications

References 24 publications

GOTPM: a parallel hybrid particle-mesh treecode

GOTPM: a parallel hybrid particle-mesh treecode

Observational probes of cosmic acceleration

The Galaxy UV Luminosity Function Before the Epoch of Reionization

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