How do the dynamics of the Milky Way -- Large Magellanic Cloud system affect gamma-ray constraints on particle dark matter?

Abstract

Previous studies on astrophysical dark matter (DM) constraints have all assumed that the Milky Way's (MW) DM halo can be modelled in isolation. However, recent work suggests that the MW's largest dwarf satellite, the Large Magellanic Cloud (LMC), has a mass of 10-20$\%$ that of the MW and is currently merging with our Galaxy. As a result, the DM haloes of the MW and LMC are expected to be strongly deformed. We here address and quantify the impact of the dynamical response caused by the passage of the LMC through the MW on the prospects for indirect DM searches. Utilising a set of state-of-the-art numerical simulations of the evolution of the MW-LMC system, we derive the DM distribution in both galaxies at the present time based on the Basis Function Expansion formalism. Consequently, we build $J$-factor all-sky maps of the MW-LMC system in order to study the impact of the LMC passage on gamma-ray indirect searches for thermally produced DM annihilating in the outer MW halo as well as within the LMC halo standalone. We conduct a detailed analysis of 12 years of Fermi-LAT data that incorporates various large-scale gamma-ray emission components and we quantify the systematic uncertainty associated with the imperfect knowledge of the astrophysical gamma-ray sources. We find that the dynamical response caused by the LMC passage can alter the constraints on the velocity-averaged annihilation cross section for weak scale particle DM at a level comparable to the existing observational uncertainty of the MW halo's density profile and total mass.

arXiv comment21 pages (15 - main body; 6 - appendices), 10 figures; text corresponds to the version published in MNRAS

References in corpus (81)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• Astropy: A Community Python Package for Astronomy
• A Universal Density Profile from Hierarchical Clustering
• The Structure of Cold Dark Matter Halos
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Asymptotic formulae for likelihood-based tests of new physics
• The Average Star Formation Histories of Galaxies in Dark Matter Halos from z=0-8
• Galactic star formation and accretion histories from matching galaxies to dark matter haloes
• Fermi Large Area Telescope Fourth Source Catalog
• The merger that led to the formation of the Milky Way's inner stellar halo and thick disk
• The mass distribution and gravitational potential of the Milky Way
• Co-formation of the Galactic disc and the stellar halo
• The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV
• PPPC 4 DM ID: A Poor Particle Physicist Cookbook for Dark Matter Indirect Detection
• New Understanding of Large Magellanic Cloud Structure, Dynamics and Orbit from Carbon Star Kinematics
• Are the Magellanic Clouds on their First Passage about the Milky Way?
• The Parkes multibeam pulsar survey: VI. Discovery and timing of 142 pulsars and a Galactic population analysis
• Detection of the Schwarzschild precession in the orbit of the star S2 near the Galactic centre massive black hole
• Third-Epoch Magellanic Cloud Proper Motions I: HST/WFC3 data and Orbit Implications
• The Fermi Galactic Center GeV Excess and Implications for Dark Matter
• The Circular Velocity Curve of the Milky Way from $5$ to $25$ kpc
• The total mass of the Large Magellanic Cloud from its perturbation on the Orphan stream
• Tango for three: Sagittarius, LMC, and the Milky Way
• Third-Epoch Magellanic Cloud Proper Motions II: The Large Magellanic Cloud Rotation Field in Three Dimensions
• The 1st Fermi Lat Supernova Remnant Catalog
• Constraints on the Galactic Halo Dark Matter from Fermi-LAT Diffuse Measurements
• Gamma Ray Signals from Dark Matter: Concepts, Status and Prospects
• A timing constraint on the (total) mass of the Large Magellanic Cloud
• Hunting for the Dark Matter Wake Induced by the Large Magellanic Cloud
• Dark Matter distribution in the Milky Way: microlensing and dynamical constraints
• Evidence for dark matter in the inner Milky Way
• The Orbital Histories of Magellanic Satellites Using Gaia DR2 Proper Motions
• And yet it moves: The dangers of artificially fixing the Milky Way center of mass in the presence of a massive Large Magellanic Cloud
• DarkSUSY 6 : An Advanced Tool to Compute Dark Matter Properties Numerically
• Reconstructing the Last Major Merger of the Milky Way with the H3 Survey
• Search for Spatially Extended Fermi-LAT Sources Using Two Years of Data
• A New Model For The Loop-I (The North Polar Spur) Region
• Response of the Milky Way's disc to the Large Magellanic Cloud in a first infall scenario
• The nature of the Diffuse Gamma-Ray Background
• The mass of our Milky Way
• Piercing the Milky Way: an all-sky view of the Orphan Stream
• Quantifying the impact of the Large Magellanic Cloud on the structure of the Milky Way's dark matter halo using Basis Function Expansions
• Measuring the Mass of the Large Magellanic Cloud with Stellar Streams Observed by $S^5$
• All-Sky Dynamical Response of the Galactic Halo to the Large Magellanic Cloud
• Limit on the LMC mass from a census of its satellites
• Detection of the Milky Way reflex motion due to the Large Magellanic Cloud infall
• Detection of the LMC-induced sloshing of the Galactic halo
• Indirect Searches for Dark Matter: a status review
• Multimessenger constraints on the dark matter interpretation of the Fermi-LAT Galactic center excess
• Deep view of the Large Magellanic Cloud with 6 years of Fermi-LAT observations
• Strong Evidence that the Galactic Bulge is Shining in Gamma Rays
• The cumulative mass profile of the Milky Way as determined by globular cluster kinematics from Gaia DR2
• Reflex motion in the Milky Way stellar halo resulting from the Large Magellanic Cloud infall
• An adaptive algorithm for n-body field expansions
• CLUMPY: a code for gamma-ray signals from dark matter structures
• CLUMPY: Jeans analysis, $\gamma$-ray and neutrino fluxes from dark matter (sub-)structures
• Proper Motions of Stellar Streams Discovered in the Dark Energy Survey
• Equilibrium models of the Milky Way mass are biased high by the LMC
• The effect of the deforming dark matter haloes of the Milky Way and the Large Magellanic Cloud on the Orphan-Chenab stream
• CLUMPY v3: $\gamma$-ray and $\nu$ signals from dark matter at all scales
• Rare and Different: Anomaly Scores from a combination of likelihood and out-of-distribution models to detect new physics at the LHC
• The Pisces Plume and the Magellanic Wake
• Search for Gamma-ray Emission from Dark Matter Annihilation in the Large Magellanic Cloud with the Fermi Large Area Telescope
• Uncertainties in the Galactic dark matter distribution: an update
• The EMU view of the Large Magellanic Cloud: Troubles for sub-TeV WIMPs
• Bayesian reconstruction of the Milky Way dark matter distribution
• Dark matter constraints from dwarf galaxies: a data-driven analysis
• 3D template-based $Fermi$-LAT constraints on the diffuse supernova axion-like particle background
• SkyFACT: High-dimensional modeling of gamma-ray emission with adaptive templates and penalized likelihoods
• A Search for Dark Matter Annihilation in the Milky Way Halo
• The highest-speed local dark matter particles come from the Large Magellanic Cloud
• A neural simulation-based inference approach for characterizing the Galactic Center $\gamma$-ray excess
• EXP: N-body integration using basis function expansions
• Hard and bright gamma-ray emission at the base of the Fermi bubbles
• Constraining the Milky Way halo kinematics via its Linear Response to the Large Magellanic Cloud
• An estimate of the DM profile in the Galactic bulge region
• Constraining Galactic dark matter with gamma-ray pixel counts statistics
• Effects on the local dark matter distribution due to the Large Magellanic Cloud