What the Milky Way's Dwarfs tell us about the Galactic Center extended excess

Abstract

The Milky Way's Galactic Center harbors a gamma-ray excess that is a candidate signal of annihilating dark matter. Dwarf galaxies remain predominantly dark in their expected commensurate emission. In this work we quantify the degree of consistency between these two observations through a joint likelihood analysis. In doing so we incorporate Milky Way dark matter halo profile uncertainties, as well as an accounting of diffuse gamma-ray emission uncertainties in dark matter annihilation models for the Galactic Center Extended gamma-ray excess (GCE) detected by the Fermi Gamma-Ray Space Telescope. The preferred range of annihilation rates and masses expands when including these unknowns. Even so, using two recent determinations of the Milky Way halo's local density leave the GCE preferred region of single-channel dark matter annihilation models to be in strong tension with annihilation searches in combined dwarf galaxy analyses. A third, higher Milky Way density determination, alleviates this tension. Our joint likelihood analysis allows us to quantify this inconsistency. We provide a set of tools for testing dark matter annihilation models' consistency within this combined dataset. As an example, we test a representative inverse Compton sourced self-interacting dark matter model, which is consistent with both the GCE and dwarfs.

v2, 12 pages, 4 figures, tools online at: https://github.com/rekeeley/GCE_errors

References in corpus (17)

• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• Searching for Dark Matter Annihilation in Recently Discovered Milky Way Satellites with Fermi-LAT
• Background model systematics for the Fermi GeV excess
• The Spectrum and Morphology of the Fermi Bubbles
• A Tale of Tails: Dark Matter Interpretations of the Fermi GeV Excess in Light of Background Model Systematics
• Dwarf galaxy annihilation and decay emission profiles for dark matter experiments
• Cosmic Ray Protons in the Inner Galaxy and the Galactic Center Gamma-Ray Excess
• Galactic Center gamma-ray "excess" from an active past of the Galactic Centre?
• Millisecond pulsars and the Galactic Center gamma-ray excess: the importance of luminosity function and secondary emission
• Spherical Jeans analysis for dark matter indirect detection in dwarf spheroidal galaxies - Impact of physical parameters and triaxiality
• Millisecond pulsar interpretation of the Galactic center gamma-ray excess
• Galactic Center Excess in Gamma Rays from Annihilation of Self-Interacting Dark Matter
• Distinguishing Dark Matter from Unresolved Point Sources in the Inner Galaxy with Photon Statistics
• Testing the millisecond pulsar scenario of the Galactic center gamma-ray excess with very high energy gamma-rays
• Mapping Extragalactic Dark Matter Annihilation with Galaxy Surveys: A Systematic Study of Stacked Group Searches
• Young Pulsars and the Galactic Center GeV Gamma-ray Excess
• Discovery of a New Galactic Center Excess Consistent with Upscattered Starlight

Cited by in corpus (9)

• A Global Analysis of Dark Matter Signals from 27 Dwarf Spheroidal Galaxies using 11 Years of Fermi-LAT Observations
• Foreground Mismodeling and the Point Source Explanation of the Fermi Galactic Center Excess
• Handling the Uncertainties in the Galactic Dark Matter Distribution for Particle Dark Matter Searches
• Structure Formation Models Weaken Limits on WIMP Dark Matter from Dwarf Spheroidal Galaxies
• A Search for Dark Matter Annihilation in the Milky Way Halo
• Direct Detection of Dark Matter -- APPEC Committee Report
• Entering the Era of Dark Matter Astronomy? Near to Long-Term Forecasts in X-Ray and Gamma-Ray Bands
• Constraints on dark matter annihilation from the FAST observation of the Coma Berenices dwarf galaxy
• Sliding into DM: Determining the local dark matter density and speed distribution using only the local circular speed of the Galaxy