Large‐scale bias and stochasticity of haloes and dark matter

By Uros Seljak Michael S. Warren. 2004

152 citations recorded by the source corpus.

On large scales, galaxies and their haloes are usually assumed to trace the dark matter with a constant bias and dark matter is assumed to trace the linear density field. We test these assumption using several large N-body simulations with 384 3 ‐1024 3 particles and box sizes of 96‐1152 h −1 Mpc, which can both resolve the small galactic-size haloes and sample the large-scale fluctuations. We explore the average halo bias relation as a function of halo mass and show that existing fitting formulae overestimate the halo bias by up to 20 per cent in the regime just below the non-linear mass. We propose a new expression that fits our simulations well. We find that the halo bias is nearly constant, b ∼ 0.65‐0.7, for masses below one-tenth of the non-linear mass. We next explore the relation between the initial and final dark matter in individual Fourier modes and show that there are significant fluctuations in their ratio, ranging from 10 per cent rms at k ∼ 0.03 h Mpc −1 to 50 per cent rms at k ∼ 0.1 h Mpc −1 .W e a rgue that these large fluctuations are caused by perturbative effects beyond the linear theory, which are dominated by long-wavelength modes with large random fluctuations. Similar or larger fluctuations exist between haloes and dark matter and between haloes of different mass. These fluctuations must be included in attempts to determine the relative bias of two populations from their maps, which would otherwise be immune to sampling variance. Ke yw ords: cosmology: theory ‐ dark matter ‐ large-scale structure of Universe.

Subfields: Astronomy and Astrophysics, Spectroscopy

View Paper: https://www.semanticscholar.org/paper/916ec126d4538aa34f9a4431a815ca72ff1f0463

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Citations in the corpus

The Luminosity and Color Dependence of the Galaxy Correlation Function (2004, methodology): “If we instead use the formula of Seljak & Warren (2004) (with the same treatment of exclusion and scale dependence), then we find negligible change in the best-fit HODs, but the predicted amplitude of wp(rp) at large scales is generally lower, increasing 2 for some samples and decreasing it for…”
THE LARGE-SCALE BIAS OF DARK MATTER HALOS: NUMERICAL CALIBRATION AND MODEL TESTS (2010, methodology): “These models produce results that are reasonably accurate but fail to reproduce in detail the bias of halos found in numerical simulations (Jing 1998; Seljak & Warren 2004; Tinker et al. 2005; Gao et al. 2005; Pillepich et al. 2008).”
Galaxy halo masses and satellite fractions from galaxy–galaxy lensing in the Sloan Digital Sky Survey: stellar mass, luminosity, morphology and environment dependencies (2005, methodology): “Therefore, rather than attempting to fit for it by fitting to the bias, we fix the bias by doing the halo model fits without the h-h term to get the halo mass, then using b(M) from Seljak & Warren (2004) to redo the fits for Mcent and α with the appropriate value of bias fixing the h-h term.”
The Physics of Galaxy Clustering. I. A Model for Subhalo Populations (2004, background): “…be used to calculate galaxy clustering statistics, including environmental dependences, in a way that explicitly accounts for complicated non-linear effects such as the bias of host halos with respect to the dark matter (Mo & White 1996; Jing 1998; Sheth, Mo, & Tormen 1999; Seljak & Warren 2004).”
Scale-dependent bias induced by local non-Gaussianity: a comparison to N-body simulations (2008, unknown): “While models with Gaussian initial conditions predict there is little stochasticity on large scales (Seljak & Warren 2004), this has not been shown explicitly for models with non-Gaussianity.”
COLOSSUS: A Python Toolkit for Cosmology, Large-scale Structure, and Dark Matter Halos (2017, methodology): “…on scale-free universes, but also applicable to ΛCDM sheth01 Sheth et al. 2001 Bias model taking the ellipsoidal nature of halos into account seljak04 Seljak & Warren 2004 Model with an optional cosmological correction term pillepich10 Pillepich et al. 2010 A numerical calibration…”
GALAXY CLUSTERING IN THE NEWFIRM MEDIUM BAND SURVEY: THE RELATIONSHIP BETWEEN STELLAR MASS AND DARK MATTER HALO MASS AT 1 < z < 2 (2010, background): “…are several different calibrations of the halo bias relation in the literature (e.g. Sheth & Tormen 1999; Sheth et al. 2001; Hamana et al. 2001; Seljak & Warren 2004; Wetzel et al. 2007; Tinker et al. 2010b), and it is of course at the high bias end of this relation, where the halos are…”
Resolving cosmic structure formation with the Millennium-II simulation (2009, methodology): “In the Mo & White model, b→ 1−δ−1c ≈ 0.4 for M M?. Sheth & Tormen (1999) and Seljak & Warren (2004), on the other hand, find b ≈ 0.7 in this same regime.”
The Canadian Cluster Comparison Project: detailed study of systematics and updated weak lensing masses (2015, methodology): “We gauge the systematic uncertainty in the correction by considering different fitting functions from the literature, namely those from Sheth & Tormen (1999), Sheth, Mo & Tormen (2001) and Seljak & Warren (2004).”
Halo mass function and scale-dependent bias from N-body simulations with non-Gaussian initial conditions (2008, methodology): “Similarly to the halo mass function, when expressed in terms of σ−1, the linear bias assumes a universal form which, within a given accuracy, is independent of redshift and just weakly dependent on cosmology (e.g. Sheth & Tormen 1999; Seljak & Warren 2004).”
Halo Assembly Bias in Hierarchical Structure Formation (2008, background): “…for assembly bias and reduces to the Press-Schechter bias when marginalized over all parameters excluding mass (note that fitting formulae for bias calibrated at lower mass, such as those proposed by Sheth & Tormen (1999) or Seljak & Warren (2004), fail in the high mass regime (Cohn & White 2007)).”