The Galactic Center GeV Excess from a Series of Leptonic Cosmic-Ray Outbursts

Abstract

It has been proposed that a recent outburst of cosmic-ray electrons could account for the excess of GeV-scale gamma rays observed from the region surrounding the Galactic Center. After studying this possibility in some detail, we identify scenarios in which a series of leptonic cosmic-ray outbursts could plausibly generate the observed excess. The morphology of the emission observed outside of $\sim 1^{\circ }-2^{\circ }$ from the Galactic Center can be accommodated with two outbursts, one which took place approximately $\sim 10^6$ years ago, and another (injecting only about 10\% as much energy as the first) about $\sim 10^5$ years ago. The emission observed from the innermost $\sim 1^{\circ }-2^{\circ }$ requires one or more additional recent outbursts and/or a contribution from a centrally concentrated population of unresolved millisecond pulsars. In order to produce a spectrum that is compatible with the measured excess (whose shape is approximately uniform over the region of the excess), the electrons from the older outburst must be injected with significantly greater average energy than those injected more recently, enabling their spectra to be similar after $\sim 10^6$ years of energy losses.

arXiv comment28 pages, 7 figures, 3 tables, 1 appendix

References in corpus (69)

• A Universal Density Profile from Hierarchical Clustering
• The Structure of Cold Dark Matter Halos
• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• MultiNest: an efficient and robust Bayesian inference tool for cosmology and particle physics
• Multimodal nested sampling: an efficient and robust alternative to MCMC methods for astronomical data analysis
• The Galactic Center Massive Black Hole and Nuclear Star Cluster
• Cosmic-ray propagation and interactions in the Galaxy
• Propagation of cosmic-ray nucleons in the Galaxy
• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• Clumps and streams in the local dark matter distribution
• The Diversity and Similarity of Simulated Cold Dark Matter Halos
• Dark Matter Annihilation in The Galactic Center As Seen by the Fermi Gamma Ray Space Telescope
• Leptonic and Hadronic Modeling of Fermi-Detected Blazars
• The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics and Formation
• On The Origin Of The Gamma Rays From The Galactic Center
• Detection of a Gamma-Ray Source in the Galactic Center Consistent with Extended Emission from Dark Matter Annihilation and Concentrated Astrophysical Emission
• The dependence of dark matter profiles on the stellar to halo mass ratio: a prediction for cusps vs cores
• Background model systematics for the Fermi GeV excess
• Dark Matter and Pulsar Model Constraints from Galactic Center Fermi-LAT Gamma Ray Observations
• Astrophysical and Dark Matter Interpretations of Extended Gamma-Ray Emission from the Galactic Center
• A Tentative Gamma-Ray Line from Dark Matter Annihilation at the Fermi Large Area Telescope
• The Spectrum and Morphology of the Fermi Bubbles
• Microwave ISM Emission Observed by WMAP
• Cosmic-Ray Nuclei, Antiprotons and Gamma-rays in the Galaxy: a New Diffusion Model
• A Tale of Tails: Dark Matter Interpretations of the Fermi GeV Excess in Light of Background Model Systematics
• A mass-dependent density profile for dark matter haloes including the influence of galaxy formation
• The Fermi Haze: A Gamma-Ray Counterpart to the Microwave Haze
• The Fermi Bubbles: Giant, Multi-Billion-Year-Old Reservoirs of Galactic Center Cosmic Rays
• The Consistency of Fermi-LAT Observations of the Galactic Center with a Millisecond Pulsar Population in the Central Stellar Cluster
• The Fermi Bubbles. I. Possible Evidence for Recent AGN Jet Activity in the Galaxy
• GeV excess in the Milky Way: The Role of Diffuse Galactic gamma ray Emission template
• Cosmic Ray Protons in the Inner Galaxy and the Galactic Center Gamma-Ray Excess
• Pulsars Cannot Account for the Inner Galaxy's GeV Excess
• The Fermi Bubbles: Supersonic AGN Jets with Anisotropic Cosmic Ray Diffusion
• WIMPs at the Galactic Center
• 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
• High energy gamma rays from the massive black hole in the Galactic Center
• The Milky Way's Fermi Bubbles: Echoes of the Last Quasar Outburst?
• Galactic center at very high-energies
• Unified interpretation of cosmic-ray nuclei and antiproton recent measurements
• Fermi gamma-ray `bubbles' from stochastic acceleration of electrons
• Origin of the Fermi Bubble
• Probing the Fermi Bubbles in Ultraviolet Absorption: A Spectroscopic Signature of the Milky Way's Biconical Nuclear Outflow
• Challenges in Explaining the Galactic Center Gamma-Ray Excess with Millisecond Pulsars
• Updated cosmic-ray and radio constraints on light dark matter: Implications for the GeV gamma-ray excess at the Galactic center
• Non-Thermal Insights on Mass and Energy Flows Through the Galactic Centre and into the Fermi Bubbles
• Millisecond pulsar interpretation of the Galactic center gamma-ray excess
• The Fermi Bubbles. II. The Potential Roles of Viscosity and Cosmic Ray Diffusion in Jet Models
• Traces of past activity in the Galactic Centre
• Diffuse gamma-ray emission from galactic pulsars
• On the Relevance of Sharp Gamma-Ray Features for Indirect Dark Matter Searches
• A description of the Galactic Center excess in the Minimal Supersymmetric Standard Model
• Low-mass X-ray binaries in the bulge of the Milky Way
• A Last Look at the Microwave Haze/Bubbles with WMAP
• A Multiwavelength View of a Mass Outflow from the Galactic Center
• Optimal angular window for observing Dark Matter annihilation from the Galactic Center region: the case of gamma-ray lines
• A Three Parsec-Scale Jet-Driven Outflow from Sgr A*
• The Fermi Gamma-Ray Haze from Dark Matter Annihilations and Anisotropic Diffusion
• A Critical Reevaluation of Radio Constraints on Annihilating Dark Matter
• Constraints on dark matter annihilations from diffuse gamma-ray emission in the Galaxy
• High Energy Neutrinos from the Fermi Bubbles
• Identification of Spinning Dust in Halpha-Correlated Microwave Emission
• Interstellar gas in the Galaxy and the X-ray luminosity of Sgr A* in the recent past
• Fermi Gamma-ray Haze via Dark Matter and Millisecond Pulsars
• Galactic Center Shells and a Recurrent Starburst Model
• Assessing the Feasibility of Cosmic-Ray Acceleration by Magnetic Turbulence at the Galactic Center
• Searching for High Energy Neutrino counterpart signals; The case of the Fermi Bubbles signal and of Dark Matter annihilation in the inner Galaxy
• Indirect dark matter searches: towards a consistent top-bottom approach for studying the gamma-ray signals and associated backgrounds

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• Constraints on dark matter annihilation and decay from the large-scale structure of the nearby universe
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• Muonphilic Dark Matter explanation of gamma-ray galactic center excess: a comprehensive analysis
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• On the GeV excess in the diffuse γ-ray emission towards the Galactic Center
• Probing the Fermi-LAT GeV excess with gravitational waves
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• Probing the pulsar explanation of the Galactic-Center GeV excess using continuous gravitational-wave searches
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