Priors on Lagrangian bias parameters from galaxy formation modelling

Zennaro, Matteo; Angulo, Raul E.; Contreras, Sergio; Pellejero-Ibáñez, Marcos; Maion, Francisco

doi:10.48550/arxiv.2110.05408

Cited by 9 publications

(18 citation statements)

References 55 publications

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“…in which s 2 (q) = s ij s ij , and s ij is the traceless part of the tidal tensor. This has the advantage of being agnostic to the galaxy formation processes, and also very flexible, allowing one to fit virtually any galaxy population merely by changing the values of the bias parameters [22]. Using equation (3.1) one can obtain an approximation for the galaxy density field in Lagrangian space; however, to compare it to observations one must have it in Eulerian space.…”

Section: Bias Expansionmentioning

confidence: 99%

Statistics of biased tracers in variance-suppressed simulations

Francisco¹,

Angulo²,

Zennaro³

2022

Preprint

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Cosmological simulations play an increasingly important role in analysing the observed large-scale structure of the Universe. Recently, they have been particularly important in building hybrid models that combine a perturbative bias expansion with displacement fields extracted from N-body simulations to describe the clustering of biased tracers. Here, we show that simulations that employ a technique referred to as "Fixing-and-pairing" (F&P) can dramatically improve the statistical precision of such hybrid models. Specifically, by numerical and analytic means, we show that F&P simulations provide unbiased estimates for all statistics employed by hybrid models while reducing, by up to two orders of magnitude, their uncertainty on large scales. This roughly implies that an EUCLID-like survey could be analysed using simulations of 2Gpc a side -a 10% of the survey volume. Our work establishes the robustness of F&P for current hybrid theoretical models for galaxy clustering, an important step towards achieving an optimal exploitation of large-scale structure measurements.

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Section: Bias Expansionmentioning

confidence: 99%

Statistics of biased tracers in variance-suppressed simulations

Francisco¹,

Angulo²,

Zennaro³

2022

Preprint

Self Cite

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“…[96], generalized to mock galaxies in refs. [97,98]. For the shotnoise term we choose a Gaussian prior on SN, centered on the Poisson value (Table 1) with a width of 30% [99].…”

Section: Parameter Priors Sampling and Emulationmentioning

confidence: 99%

Cosmological constraints from the tomographic cross-correlation of DESI Luminous Red Galaxies and Planck CMB lensing

White,

Zhou,

DeRose

et al. 2021

Preprint

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We use luminous red galaxies selected from the imaging surveys that are being used for targeting by the Dark Energy Spectroscopic Instrument (DESI) in combination with CMB lensing maps from the Planck collaboration to probe the amplitude of large-scale structure over 0.4 ≤ z ≤ 1. Our galaxy sample, with an angular number density of approximately 500 deg −2 over 18,000 sq.deg., is divided into 4 tomographic bins by photometric redshift and the redshift distributions are calibrated using spectroscopy from DESI. We fit the galaxy autospectra and galaxy-convergence cross-spectra using models based on cosmological perturbation theory, restricting to large scales that are expected to be well described by such models. Within the context of ΛCDM, combining all 4 samples and using priors on the background cosmology from supernova and baryon acoustic oscillation measurements, we find S 8 = σ 8 (Ω m /0.3) 0.5 = 0.73 ± 0.03. This result is lower than the prediction of the ΛCDM model conditioned on the Planck data. Our data prefer a slower growth of structure at low redshift than the model predictions, though at only modest significance.

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“…Similar work, for galaxies in IllustrisTNG (Nelson et al 2021), has been explored recently (Barreira et al 2021). As this work was being finalized, Zennaro et al (2021b) used hybrid EFT models precisely in this way to study the distributions of second-order Lagrangian bias for samples of galaxies populated using an extended sub-halo abundance matching scheme. at kmax ∼ 0.4 hMpc −1 is not inconsistent with the results of the work of Kokron et al (2021) which fit power spectra to kmax = 0.6 hMpc −1 (and recently Zennaro et al (2021b) which go to even smaller scales).…”

Section: Discussionmentioning

confidence: 93%

“…As this work was being finalized, Zennaro et al (2021b) used hybrid EFT models precisely in this way to study the distributions of second-order Lagrangian bias for samples of galaxies populated using an extended sub-halo abundance matching scheme. at kmax ∼ 0.4 hMpc −1 is not inconsistent with the results of the work of Kokron et al (2021) which fit power spectra to kmax = 0.6 hMpc −1 (and recently Zennaro et al (2021b) which go to even smaller scales). Those publications were concerned with fitting the clustering and lensing power spectra, while in this publication we concern ourselves with the significantly more difficult problem of describing the full statistical properties of the field that encapsulates information from all N -point functions.…”

Section: Discussionmentioning

confidence: 99%

Priors on red galaxy stochasticity from hybrid effective field theory

Kokron,

DeRose,

Chen

et al. 2021

Preprint

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We investigate the stochastic properties of typical red galaxy samples in a controlled numerical environment. We use Halo Occupation Distribution (HOD) modelling to create mock realizations of three separate bright red galaxy samples consistent with datasets used for clustering and lensing analyses in modern galaxy surveys. Second-order Hybrid Effective Field Theory (HEFT) is used as a field-level forward model to describe the full statistical distribution of these tracer samples, and their stochastic power spectra are directly measured and compared to the Poisson shot-noise prediction. While all of the galaxy samples we consider are hosted within haloes with sub-Poisson stochasticity, we observe that the galaxy samples themselves possess stochasticities that range from sub-Poisson to super-Poisson, in agreement with predictions from the halo model. As an application of our methodology, we place priors on the expected degree of non-Poisson stochasticity in cosmological analyses using such samples. We expect these priors will be useful in reducing the complexity of the full parameter space for future analyses using second-order Lagrangian bias models. More generally, the techniques outlined here present the first application of hybrid EFT methods to characterize models of the galaxy-halo connection at the field level, revealing new connections between once-disparate modelling frameworks.

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Priors on Lagrangian bias parameters from galaxy formation modelling

Cited by 9 publications

References 55 publications

Statistics of biased tracers in variance-suppressed simulations

Statistics of biased tracers in variance-suppressed simulations

Cosmological constraints from the tomographic cross-correlation of DESI Luminous Red Galaxies and Planck CMB lensing

Priors on red galaxy stochasticity from hybrid effective field theory

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