Dark Matter Velocity Distributions for Direct Detection: Astrophysical Uncertainties are Smaller Than They Appear

Abstract

The sensitivity of direct detection experiments depends on the phase-space distribution of dark matter near the Sun, which can be modeled theoretically using cosmological hydrodynamical simulations of Milky Way-like galaxies. However, capturing the halo-to-halo variation in the local dark matter speeds -- a necessary step for quantifying the astrophysical uncertainties that feed into experimental results -- requires a sufficiently large sample of simulated galaxies, which has been a challenge. In this Letter, we quantify this variation with nearly 100 Milky Way-like galaxies from the TNG50 simulation, the largest sample to date at this resolution. Moreover, we introduce a novel phase-space scaling procedure that endows every system with a reference frame that accurately reproduces the local standard-of-rest speed of our Galaxy, providing a principled way of extrapolating the simulation results to real-world data. The ensemble of predicted speed distributions is well characterized by the standard halo model, a Maxwell-Boltzmann distribution truncated at the escape speed, though the individual distributions can deviate from it, especially at high speeds. The dark matter-nucleon cross section limits placed by these speed distributions vary by ~60% about the median. This places the 1-sigma astrophysical uncertainty at or below the level of the systematic uncertainty of current ton-scale detectors, even down to the energy threshold. The predicted uncertainty remains unchanged when subselecting on those TNG50 galaxies with merger histories similar to the Milky Way. Tabulated speed distributions, as well as Maxwell-Boltzmann fits, are provided for use in computing direct detection bounds or projecting sensitivities.

Published version. 7 pages, 4 figures; 2 pages of end matter with 2 additional figures. Data for this work are available at https://github.com/folsomde/DM_velocity_distributions

References in corpus (75)

• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Populating a cluster of galaxies - I. Results at z=0
• Local Kinematics and the Local Standard of Rest
• Dark Matter Search Results from a One Tonne$\times$Year Exposure of XENON1T
• The Galaxy in Context: Structural, Kinematic and Integrated Properties
• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• The Milky Way Tomography with SDSS: I. Stellar Number Density Distribution
• The merger that led to the formation of the Milky Way's inner stellar halo and thick disk
• FIRE-2 Simulations: Physics versus Numerics in Galaxy Formation
• Substructures in hydrodynamical cluster simulations
• Co-formation of the Galactic disc and the stellar halo
• First Results from the TNG50 Simulation: Galactic outflows driven by supernovae and black hole feedback
• First Results from the TNG50 Simulation: The evolution of stellar and gaseous disks across cosmic time
• The Proper Motion of Sgr A*: II. The Mass of Sgr A*
• Reconciling dwarf galaxies with LCDM cosmology: Simulating a realistic population of satellites around a Milky Way-mass galaxy
• The APOSTLE simulations: solutions to the Local Group's cosmic puzzles
• The Auriga Project: the properties and formation mechanisms of disc galaxies across cosmic time
• Structural Properties of Pseudo-Bulges, Classical Bulges and Elliptical Galaxies: an SDSS Perspective
• A direct dynamical measurement of the Milky Way's disk surface density profile, disk scale length, and dark matter profile at 4 kpc < R < 9 kpc
• First Dark Matter Search with Nuclear Recoils from the XENONnT Experiment
• The Milky Way: An Exceptionally Quiet Galaxy; Implications for the formation of spiral galaxies
• The Milky Way's Stellar Disk
• Dark Matter Direct Detection with Non-Maxwellian Velocity Structure
• Phase-space structure in the local dark matter distribution and its signature in direct detection experiments
• The APOSTLE project: Local Group kinematic mass constraints and simulation candidate selection
• Improved GRAVITY astrometric accuracy from modeling of optical aberrations
• The Astrophysical Uncertainties Of Dark Matter Direct Detection Experiments
• Dark matter local density determination: recent observations and future prospects
• Dark Matter Search Results from 4.2 Tonne-Years of Exposure of the LUX-ZEPLIN (LZ) Experiment
• A Next-Generation Liquid Xenon Observatory for Dark Matter and Neutrino Physics
• Apocenter Pile-Up: Origin of the Stellar Halo Density Break
• Dark matter response to galaxy formation
• The origin of galactic metal-rich stellar halo components with highly eccentric orbits
• Public data release of the FIRE-2 cosmological zoom-in simulations of galaxy formation
• Star formation histories of dwarf galaxies in the FIRE simulations: dependence on mass and Local Group environment
• Dark Matter Direct Detection Signals inferred from a Cosmological N-body Simulation with Baryons
• The fine-grained phase-space structure of Cold Dark Matter halos
• The Milky Way Halo in Action Space
• Inferred Evidence For Dark Matter Kinematic Substructure with SDSS-Gaia
• Chemo-kinematics of the $Gaia$ RR Lyrae: the halo and the disc
• Simulated Milky Way analogues: implications for dark matter direct searches
• The Distribution of Dark Matter in the Milky Way's Disk
• The Halo's Ancient Metal-Rich Progenitor Revealed with BHB Stars
• Direct detection of self-interacting dark matter
• Effect of Gravitational Focusing on Annual Modulation in Dark-Matter Direct-Detection Experiments
• NIHAO project II: Halo shape, phase-space density and velocity distribution of dark matter in galaxy formation simulations
• Galactic Archaeology with Gaia
• Dependence of direct detection signals on the WIMP velocity distribution
• The Earth's velocity for direct detection experiments
• Dark Shards: velocity substructure from Gaia and direct searches for dark matter
• Direct detection of WIMPs
• Assessing Astrophysical Uncertainties in Direct Detection with Galaxy Simulations
• The impact of baryons on the direct detection of dark matter
• Radial velocity moments of dark matter haloes
• The merger and assembly histories of Milky Way- and M31-like galaxies with TNG50: disk survival through mergers
• Improving constraints on the extended mass distribution in the Galactic Center with stellar orbits
• Implications of hydrodynamical simulations for the interpretation of direct dark matter searches
• The highest-speed local dark matter particles come from the Large Magellanic Cloud
• Galactic Rotation from Cepheids with Gaia DR2 and Effects of Non-Axisymmetry
• Does the Milky Way Obey Spiral Galaxy Scaling Relations?
• A universal velocity distribution of relaxed collisionless structures
• Are the Milky Way and Andromeda unusual? A comparison with Milky Way and Andromeda Analogs
• The dark matter component of the Gaia radially anisotropic substructure
• The impact of the Large Magellanic Cloud on dark matter direct detection signals
• A Bayesian estimation of the Milky Way's circular velocity curve using Gaia DR3
• Informing dark matter direct detection limits with the ARTEMIS simulations
• Effects on the local dark matter distribution due to the Large Magellanic Cloud
• The building up of observed stellar scaling relations of massive galaxies and the connection to black hole growth in the TNG50 simulation
• Impact of uncertainties in the halo velocity profile on direct detection of sub-GeV dark matter
• Sliding into DM: Determining the local dark matter density and speed distribution using only the local circular speed of the Galaxy
• Gusts in the Headwind: Uncertainties in Direct Dark Matter Detection
• Cosmological simulations of the same spiral galaxy: connecting the dark matter distribution of the host halo with the subgrid baryonic physics
• Cosmological Simulations of Stellar Halos with Gaia Sausage-Enceladus Analogues: Two Sausages, One Bun?
• Deciphering the Kinematic Substructure of Local Dark Matter with LAMOST K Giants
• 2024 TASI Lectures: A Dark Matter Primer

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