A probabilistic deep learning model to distinguish cusps and cores in dwarf galaxies

Abstract

Numerical simulations within a cold dark matter (DM) cosmology form halos whose density profiles have a steep inner slope (`cusp'), yet observations of galaxies often point towards a flat central `core'. We develop a convolutional mixture density neural network model to derive a probability density function (PDF) of the inner density slopes of DM halos. We train the network on simulated dwarf galaxies from the NIHAO and AURIGA projects, which include both DM cusps and cores: line-of-sight velocities and 2D spatial distributions of their stars are used as inputs to obtain a PDF representing the probability of predicting a specific inner slope. The model recovers accurately the expected DM profiles: $\sim$82$\%$ of the galaxies have a derived inner slope within $\pm$0.1 of their true value, while $\sim$98$\%$ within $\pm$0.3. We apply our model to four Local Group dwarf spheroidal galaxies and find results consistent with those obtained with the Jeans modelling based code GravSphere: the Fornax dSph has a strong indication of possessing a central DM core, Carina and Sextans have cusps (although the latter with large uncertainties), while Sculptor shows a double peaked PDF indicating that a cusp is preferred, but a core can not be ruled out. Our results show that simulation-based inference with neural networks provide a innovative and complementary method for the determination of the inner matter density profiles in galaxies, which in turn can help constrain the properties of the elusive DM.

arXiv comment14 pages, 11 figures, submitted to MNRAS. comments welcome

References in corpus (50)

• Planck 2015 results. XIII. Cosmological parameters
• The Structure of Cold Dark Matter Halos
• UMAP: Uniform Manifold Approximation and Projection for Dimension Reduction
• Observational evidence for self-interacting cold dark matter
• Small-Scale Challenges to the $\Lambda$CDM Paradigm
• The SAURON project - IV. The mass-to-light ratio, the virial mass estimator and the fundamental plane of elliptical and lenticular galaxies
• At the heart of the matter: the origin of bulgeless dwarf galaxies and Dark Matter cores
• High-Resolution Rotation Curves and Galaxy Mass Models from THINGS
• How supernova feedback turns dark matter cusps into cores
• Star Formation and Feedback in Smoothed Particle Hydrodynamic Simulations--I. Isolated Galaxies
• SPARC: Mass Models for 175 Disk Galaxies with Spitzer Photometry and Accurate Rotation Curves
• A Method for Measuring (Slopes of) the Mass Profiles of Dwarf Spheroidal Galaxies
• The Cores of Dwarf Galaxy Halos
• Empirical models for Dark Matter Halos. I. Nonparametric Construction of Density Profiles and Comparison with Parametric Models
• The cored distribution of dark matter in spiral galaxies
• The Auriga Project: the properties and formation mechanisms of disc galaxies across cosmic time
• Dark Matter Halos as Particle Colliders: A Unified Solution to Small-Scale Structure Puzzles from Dwarfs to Clusters
• The dependence of dark matter profiles on the stellar to halo mass ratio: a prediction for cusps vs cores
• NIHAO project I: Reproducing the inefficiency of galaxy formation across cosmic time with a large sample of cosmological hydrodynamical simulations
• The Impact of Baryonic Physics on the Structure of Dark Matter Halos: the View from the FIRE Cosmological Simulations
• High-Resolution Measurements of the Halos of Four Dark Matter-Dominated Galaxies: Deviations from a Universal Density Profile
• The kinematic status and mass content of the Sculptor dwarf spheroidal galaxy
• NIHAO IV: Core creation and destruction in dark matter density profiles across cosmic time
• A mass-dependent density profile for dark matter haloes including the influence of galaxy formation
• Stellar Velocities in the Carina, Fornax, Sculptor and Sextans dSph Galaxies: Data from the Magellan/MMFS Survey
• Does the Fornax dwarf spheroidal have a central cusp or core?
• Dark matter heats up in dwarf galaxies
• Maximum Feedback and Dark Matter Profiles of Dwarf Galaxies
• The importance of tides for the Local Group dwarf spheroidals
• Gaia early DR3 systemic motions of Local Group dwarf galaxies and orbital properties with a massive Large Magellanic Cloud
• Estimating Black Hole Masses in Triaxial Galaxies
• Baryon-induced dark matter cores in the EAGLE simulations
• A Virial Core in the Sculptor Dwarf Spheroidal Galaxy
• First Clear Signature of an Extended Dark Matter Halo in the Draco Dwarf Spheroidal
• Diversity of dark matter density profiles in the Galactic dwarf spheroidal satellites
• Orbit-based dynamical models of the Sculptor dSph galaxy
• Model comparison of the dark matter profiles of Fornax, Sculptor, Carina and Sextans
• On the dark matter profile in Sculptor: Breaking the $\beta$ degeneracy with Virial shape parameters
• Expanded haloes, abundance matching and too-big-to-fail in the Local Group
• Local Group Dwarf Elliptical Galaxies: I. Mapping the Dynamics of NGC 205 Beyond the Tidal Radius
• A Robust and Efficient Deep Learning Method for Dynamical Mass Measurements of Galaxy Clusters
• A discrete chemo-dynamical model of the dwarf spheroidal galaxy Sculptor: mass profile, velocity anisotropy and internal rotation
• Hints against the cold and collisionless nature of dark matter from the galaxy velocity function
• Andromeda XXI -- a dwarf galaxy in a low density dark matter halo
• Action-based dynamical models of dwarf spheroidal galaxies: application to Fornax
• NIHAO -- XXV. Convergence in the cusp-core transformation of cold dark matter haloes at high star formation thresholds
• Dynamical mass inference of galaxy clusters with neural flows
• NIHAO-XXIII: Dark Matter density shaped by Black Hole feedback
• Simulation-based inference of dynamical galaxy cluster masses with 3D convolutional neural networks
• Recovering the mass profile and orbit anisotropy of mock dwarf galaxies with Schwarzschild modelling