Biased Tracers of Two Fluids in the Lagrangian Picture

Abstract

We explore Lagrangian perturbation theory (LPT) for biased tracers in the presence of two fluids, focusing on the case of cold dark matter (CDM) and baryons. The presence of two fluids induces corrections to the Lagrangian bias expansion and tracer advection, both of which we formulate as expansions in the three linear modes of the Lagrangian equations of motion. We compute the linear-order two-fluid corrections in the Zeldovich approximation, finding that modifications to the bias expansion and tracer advection both enter as percent-level corrections over a large range of wavenumbers at low redshift and draw parallels with the Eulerian formalism. We then discuss nonlinear corrections in the two-fluid picture, and calculate contributions from the relative velocity effect ($\propto v_r^2$) at one loop order. Finally, we conduct an exploratory Fisher analysis to assess the impact of two-fluid corrections on baryon acoustic oscillations (BAO) measurements, finding that while modest values of the relative bias parameters can introduce systematic biases in the measured BAO scale of up to $0.5\sigma$, fitting for these effects as additional parameters increases the error bar by less than $30\%$ across a wide range of bias values.

31 pages, 11 figures. Revised to match version accepted by JCAP

References in corpus (19)

• The DESI Experiment Part I: Science,Targeting, and Survey Design
• The Effective Field Theory of Cosmological Large Scale Structures
• Improving Cosmological Distance Measurements by Reconstruction of the Baryon Acoustic Peak
• Resumming Cosmological Perturbations via the Lagrangian Picture: One-loop Results in Real Space and in Redshift Space
• Reconstructing Baryon Oscillations: A Lagrangian Theory Perspective
• Modeling scale-dependent bias on the baryonic acoustic scale with the statistics of peaks of Gaussian random fields
• Calibrating the Baryon Oscillation Ruler for Matter and Halos
• Large-scale BAO signatures of the smallest galaxies
• Probing dark energy with the shear-ratio geometric test
• Analytic Prediction of Baryonic Effects from the EFT of Large Scale Structures
• Nonlinear power spectrum in the presence of massive neutrinos: perturbation theory approach, galaxy bias and parameter forecasts
• The Gaussian streaming model and Lagrangian effective field theory
• Halo bias in mixed dark matter cosmologies
• Reconstruction within the Zeldovich approximation
• Massive Neutrinos in Cosmology: Analytic Solutions and Fluid Approximation
• Structure formation with massive neutrinos: going beyond linear theory
• Scale-dependent bias in the BAO-scale intergalactic neutral hydrogen
• The Effective Field Theory of Large-Scale Structure in the presence of Massive Neutrinos
• Excursion set peaks: the role of shear

Cited by in corpus (18)

• A new analysis of galaxy 2-point functions in the BOSS survey, including full-shape information and post-reconstruction BAO
• Large-scale dark matter simulations
• Redshift-Space Distortions in Lagrangian Perturbation Theory
• Simulations and symmetries
• Higher-order initial conditions for mixed baryon-CDM simulations
• Unveiling dark fifth forces with linear cosmology
• Baryon Acoustic Oscillation Theory and Modelling Systematics for the DESI 2024 results
• Cosmological perturbations for two cold fluids in $\Lambda$CDM
• Unveiling dark forces with measurements of the Large Scale Structure of the Universe
• The Ly$\alpha$ forest flux correlation function: a perturbation theory perspective
• Cosmological Vlasov-Poisson equations for dark matter: Recent developments and connections to selected plasma problems
• Avoiding baryonic feedback effects on neutrino mass measurements from CMB lensing
• An Analytic Hybrid Halo + Perturbation Theory Model for Small-scale Correlators: Baryons, Halos, and Galaxies
• Optical depth to reionization from perturbative 21cm clustering
• New Interpretations of the Cosmological Preference for a Negative Neutrino Mass
• The Effective Field Theory of Large Scale Structure for Mixed Dark Matter Scenarios
• Dark Matter Recoupling
• Cosmic voids and BAO with relative baryon-CDM perturbations