Abstract
We test the regime of validity of the one-loop galaxy bias for a wide variety of biased tracers. Our most stringent test asks the bias model to simultaneously match the galaxy-galaxy and galaxy-mass spectrum, using the measured nonlinear matter spectrum from the simulations to test the one-loop effects from the bias expansion alone. In addition, we investigate the relevance of short-range nonlocality and halo exclusion through higher-derivative and scale-dependent noise terms, as well as the impact of using coevolution relations to reduce the number of free fitting parameters. From comparing the validity and merit of these assumptions, we find that a four-parameter model (linear, quadratic, cubic nonlocal bias, and constant shot noise) with a fixed quadratic tidal bias provides a robust modeling choice for the auto power spectrum of the less massive halos in our set of samples and their galaxy populations [up to ${k}_{\mathrm{max}}=0.35\text{ }\text{ }h/\mathrm{Mpc}$ for a sample volume of $6\text{ }\text{ }(\mathrm{Gpc}/h{)}^{3}$]. For the more biased tracers, it is most beneficial to include scale-dependent noise. This is also the preferred option when considering combinations of the auto and cross power spectrum, which might be relevant in joint studies of galaxy clustering and weak lensing. We also test the use of perturbation theory to account for matter loops through gRPT, EFT, and the hybrid approach RESPRESSO. While all these have similar performance, we find the latter to be the best in terms of validity and recovered mean posterior values, in accordance with it being based partially on simulations.
Highlights
The varying degrees of clustering displayed by different types of galaxies, or clusters of galaxies, has led to the understanding that these objects cannot be unbiased tracers of the underlying matter distribution (e.g., [1,2,3,4,5,6], for a recent review, see [7])
We use the measured nonlinear matter spectrum in place of Pmm, as this allows us to concentrate on bias independently of any issues related to the nonlinear evolution of matter description
In order to simplify this comparison, we only focus on the case that includes scale-dependent noise and constrains γ2 to follow the excursion set relation, which we previously identified as giving consistent results over a large range of scales, independent of the particular sample under consideration
Summary
The varying degrees of clustering displayed by different types of galaxies, or clusters of galaxies, has led to the understanding that these objects cannot be unbiased tracers of the underlying matter distribution (e.g., [1,2,3,4,5,6], for a recent review, see [7]). Since models with more degrees of freedom give rise to larger parameter uncertainties, we compare these validity estimates with a measure of the model’s merit to discern how many and which parameters constitute an optimal choice, following [52] We perform this analysis for the auto power spectrum and in combination with the cross power spectrum between galaxies/halos and matter, as consistency between the two statistics provides an even more stringent test of the bias model and is of great relevance for joint studies of galaxy clustering and weak lensing data.
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