Gravity and Large-Scale Nonlocal Bias

By Kwan Chuen Chan, R. Scoccimarro, R. Sheth. 2012

237 citations recorded by the source corpus.

The relationship between galaxy and matter overdensities, bias, is most often assumed to be local. This is however unstable under time evolution, we provide proofs under several sets of assumptions. In the simplest model galaxies are created locally and linearly biased at a single time, and subsequently move with the matter (no velocity bias) conserving their comoving number density (no merging). We show that, after this formation time, the bias becomes unavoidably non-local and non-linear at large scales. We identify the non-local gravitationally induced fields in which the galaxy overdensity can be expanded, showing that they can be constructed out of the invariants of the deformation tensor (Galileons). In addition, we show that this result persists if we include an arbitrary evolution of the comoving number density of tracers. We then include velocity bias, and show that new contributions appear, a dipole field being the signature at second order. We test these predictions by studying the dependence of halo overdensities in cells of fixed matter density: measurements in simulations show that departures from the mean bias relation are strongly correlated with the non-local gravitationally induced fields identified by our formalism. The effects on non-local bias seen in the simulations are most important for the most biased halos, as expected from our predictions. The non-locality seen in the simulations is not fully captured by assuming local bias in Lagrangian space. Accounting for these effects when modeling galaxy bias is essential for correctly describing the dependence on triangle shape of the galaxy bispectrum, and hence constraining cosmological parameters and primordial non-Gaussianity. We show that using our formalism we remove an important systematic in the determination of bias parameters from the galaxy bispectrum, particularly for luminous galaxies. (abridged)

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/42024845770c9ef678b8b9cd0328a796c41eec5c

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Citations in the corpus

The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Cosmological implications of the configuration-space clustering wedges (2016, background): “First, under local Lagrangian bias, the non-local bias parameters are related to the linear bias b1 as (Fry 1996; Catelan et al. 1998; Catelan, Porciani & Kamionkowski 2000; Chan et al. 2012) γ2 = −2 7 (b1 − 1), (13) γ −3 = 11 42 (b1 − 1).”
The power spectrum and bispectrum of SDSS DR11 BOSS galaxies – I. Bias and gravity (2014, background): “Under this assumption, the non-local bias terms can be related at first order to the linear bias term b1,3 bs2 = − 4 7 (b1 − 1) (Baldauf et al. 2012; Chan et al. 2012), (20) b3nl = 32 315 (b1 − 1) (Beutler et al. 2014; Saito et al. 2014).”
Single-field consistency relations of large scale structure part II: resummation and redshift space (2013, background): “The result that we obtained remains qualitatively the same if A or B represent extended objects, for example a fluid of galaxies of a given kind [18].”
The MICE Grand Challenge lightcone simulation – II. Halo and galaxy catalogues (2013, methodology): “For smaller scales, MICE-GC and MICE-IR deviate clearly from the simple local model and track well the non-local prediction from Chan et al. (2012), see Fig.”
The completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: BAO and RSD measurements from anisotropic clustering analysis of the quasar sample in configuration space between redshift 0.8 and 2.2 (2020, background): “If we consider all scalar invariants of the tensor ∇i jΦ(x, τ) for the gravitational potential, and ∇i jΦv(x, τ) for the velocity potential, only three invariants exists in three dimensions (see Chan et al. 2012; Eggemeier et al. 2019).”
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Testing gravity with redshift-space distortions using the power spectrum multipoles (2013, result): “…bias picture in which the initial non-local bias is neglected, we can predict the amplitude of the non-local bias as (Baldauf et al. 2012; Chan et al. 2012; Saito et al. 2014) bs2 = −4 7 (b1 − 1), (54) b3nl = 32 315 (b1 − 1), (55) which are in good agreement with the values measured in…”
Modelling baryon acoustic oscillations with perturbation theory and stochastic halo biasing (2013, unknown): “…Mo & White 1996; Dekel & Lahav 1999; Sheth & Lemson 1999; Seljak 2000; Berlind & Weinberg 2002; Smith et al. 2007; Desjacques et al. c© 0000 RAS, MNRAS000, 000–000 2010; Beltrán Jiménez & Durrer 2011; Valageas & Nishimichi 2011; Elia et al. 2012; Chan et al. 2012; Baldauf et al. 2012, 2013).”
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the power spectrum and bispectrum of the DR12 BOSS galaxies (2016, background): “This allows us to set the values of bs2 and b3nl as functions of b1 (Baldauf et al. 2012; Chan et al. 2012; Saito et al. 2014), bs2 = −4/7(b1 − 1) and b3nl = 32/315(b1 − 1), meaning that only two bias parameters need to be fitted.”
Consistent modeling of velocity statistics and redshift-space distortions in one-loop perturbation theory (2020, unknown): “[75, 76]).”