PTHALOS: a fast method for generating mock galaxy distributions

By R. Scoccimarro, R. Sheth. 2001

157 citations recorded by the source corpus.

Current models of galaxy formation applied to understanding the large-scale structure of the Universe have two parts. The first is an accurate solution of the equations of motion for the dark matter caused by gravitational clustering. The second consists of making physically reasonable approximations to the behaviour of baryons inside dark matter haloes. The first uses large, computationally intensive, N-body simulations. We argue that because the second step is, at least at present, uncertain, it is possible to obtain similar galaxy distributions without solving the first step exactly. We describe an algorithm that is several orders of magnitude faster than N-body simulations, but that is, nevertheless, rather accurate. The algorithm combines perturbation theory with virialized halo models of the non-linear density and velocity fields. For two- and three-point statistics the resulting fields are exact on large scales, and rather accurate well into the non-linear regime, particularly for two-point statistics in real and redshift space. We then show how one can use this algorithm to generate mock galaxy distributions from halo occupation numbers. As a first application, we show that it provides a good description of the clustering of galaxies in the PSCz survey. We also discuss applications to the estimation of non-Gaussian contributions to the error bars and the covariance matrix of the power spectrum, in real and redshift space, for galaxies and dark matter. The results for the latter show good agreement with simulations, supporting the use of our method for constraining cosmological parameters from forthcoming galaxy surveys.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/4ccaecdc918eec526e6387694477c636a2844d57

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Citations in the corpus

Shapes and Alignments of Galaxy Cluster Halos (2004, methodology): “…can be used to extend approximate methods for creating nonlinear representations of the matter distribution based on the halo model description (Scoccimarro & Sheth 2002) by incorporating an ensemble of ellipsoidal halos with correlated orientations and aligned position and velocity ellipsoids.”
The morphology of H ii regions during reionization (2006, methodology): “This method for adding unresolved haloes is similar to the PThalos halo algorithm, an algorithm to quickly generate mock galaxy surveys (Scoccimarro & Sheth 2002).”
INTENSITY MAPPING WITH CARBON MONOXIDE EMISSION LINES AND THE REDSHIFTED 21 cm LINE (2011, methodology): “This is done using a merger tree algorithm similar to the PThalo code (Scoccimarro & Sheth 2002), a widely used code for rapidly generating mock galaxy surveys.”
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: analysis of potential systematics (2012, methodology): “This method is inspired by the perturbation theory haloes (PTHalos) paper of Scoccimarro & Sheth (2002), and have been calibrated using 40 N-body galaxy and halo mock catalogues generated using the LASDAMAS simulations4 (McBride et al., in preparation).”
Modelling baryon acoustic oscillations with perturbation theory and stochastic halo biasing (2013, background): “Second, we usea statistical model applied to that field to produce a distribuion of halos with power spectra matching those obtained from the BigMultiDarkN -body simulations, as opposed to other methods, which rely on the halos obtained with the corresponding approximation(e.g. PTHALOS, PINOCCHIO or”
Inside-out or outside-in: the topology of reionization in the photon-starved regime suggested by Lyα forest data (2008, methodology): “Our method is a somewhat simpler version ofal- gorithms based on Lagrangian perturbation theory (Monaco et al. 2002; Scoccimarro & Sheth 2002).”
Galaxy Clustering in Early Sloan Digital Sky Survey Redshift Data (2002, methodology): “(Scoccimarro & Sheth 2002 present a novel method that should improve the computational practicality of this approach for largescale surveys.)”
The clustering of galaxies in the SDSS-III DR9 Baryon Oscillation Spectroscopic Survey: constraints on primordial non-Gaussianity (2012, methodology): “These simulations were produced using a 2nd-order Lagrangian Perturbation Theory (2LPT) approach inspired by the Perturbation Theory Halos (PTHalos; Scoccimarro & Sheth 2002) model.”
The Quijote Simulations (2019, methodology): “Its accuracy is comparable to that of the training simulations and much more than that of 2LPT commonly used to generate galaxy mocks (e.g. Scoccimarro & Sheth 2002), while at a much lower computation cost.”
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological implications of the full shape of the clustering wedges in the data release 10 and 11 galaxy samples (2013, methodology): “These mocks were constructed from two sets of PTHALOS realizations (Scoccimarro & Sheth 2002), corresponding to our fiducial cosmology, as described in Manera et al. (2013, 2014).1 Our CMASS mocks are based on 600 independent simulations with a box size of Lbox = 2.4 h−1 Gpc, while those of the…”
The Three-Dimensional Power Spectrum of Galaxies from the Sloan Digital Sky Survey (2003, methodology): “The first consists of 275 simulations constructed with the PThalos code (Scoccimarro & Sheth 2002), covering 1395 square degrees with an angular completeness map corresponding to the northern part of SDSS (sample9, an earlier version of sample11 discussed in Appendix A.”
The Initial Conditions of the Universe from Constrained Simulations (2012, methodology): “We should also remind that the structure formation model we are using is simplified and especially fails in low density regions (see Scoccimarro & Sheth 2002).”
GALAXY CLUSTERING IN THE COMPLETED SDSS REDSHIFT SURVEY: THE DEPENDENCE ON COLOR AND LUMINOSITY (2010, methodology): “Our own tests of the jackknife method on PTHalos mock catalogs (Scoccimarro & Sheth 2002), described by Zehavi et al. (2002, 2004) and Z05, show that it yields error and covariance estimates similar to those derived from multiple independent catalogs (see Z05, Figure 2).”
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: mock galaxy catalogues for the BOSS Final Data Release (2015, background): “A few pioneering works explored a viable strategy more than a decade ago relying on simplified fast gravity solvers using perturbation theory (PT): PINOCCHIO (Monaco et al. 2002, 2013) and PTHALOS (Scoccimarro & Sheth 2002).”