The characteristics of the Galactic center excess measured with 11 years of Fermi-LAT data

Abstract

The excess of $\gamma$ rays in the data measured by Fermi-LAT from the Galactic center region is one of the most intriguing mysteries in Astroparticle Physics. This Galactic center excess (GCE), has been measured with respect to different interstellar emission models (IEMs), source catalogs, data selections and techniques. Although several proposed interpretations have appeared in the literature, there are not firm conclusions as to its origin. The main difficulty in solving this puzzle lies in modeling a region of such complexity and thus precisely measuring the characteristics of the GCE. In this paper, we use 11 years of Fermi-LAT data, state of the art IEMs, and the newest 4FGL source catalog to provide precise measurements of the energy spectrum, spatial morphology, position, and sphericity of the GCE. We find that the GCE has a spectrum which is peaked at a few GeV and is well fit with a log-parabola. The normalization of the spectrum changes by roughly $60\%$ when using different IEMs, data selections and analysis techniques. The spatial distribution of the GCE is compatible with a dark matter (DM) template produced with a generalized NFW density profile with slope $\gamma =1.2-1.3$. No energy evolution is measured for the GCE morphology between $0.6-30$ GeV at a level larger than $10\%$ of the $\gamma$ average value, which is 1.25. The analysis of the GCE modeled with a DM template divided into quadrants shows that the spectrum and spatial morphology of the GCE is similar in different regions around the Galactic center. Finally, the GCE centroid is compatible with the Galactic center, with best-fit position between $l=[-0.3^{\circ },0.0^{\circ }],b=[-0.1^{\circ },0.0^{\circ }]$, and it is compatible with a spherical symmetric morphology. In particular, fitting the DM spatial profile with an ellipsoid gives a major-to-minor axis ratio between 0.8-1.2.

arXiv comment21 pages and 15 figures. Phys. Rev. D 103, 063029 (2021)

References in corpus (48)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• A Universal Density Profile from Hierarchical Clustering
• Fermi Large Area Telescope Fourth Source Catalog
• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• Planck 2013 results. XI. All-sky model of thermal dust emission
• Dark Matter Annihilation in The Galactic Center As Seen by the Fermi Gamma Ray Space Telescope
• Production and propagation of cosmic-ray positrons and electrons
• Fermi-LAT Observations of the Diffuse Gamma-Ray Emission: Implications for Cosmic Rays and the Interstellar Medium
• Diffuse continuum gamma rays from the Galaxy
• The Parkes multibeam pulsar survey: VI. Discovery and timing of 142 pulsars and a Galactic population analysis
• On The Origin Of The Gamma Rays From The Galactic Center
• Diffuse Galactic continuum gamma rays. A model compatible with EGRET data and cosmic-ray measurements
• The Characterization of the Gamma-Ray Signal from the Central Milky Way: A Compelling Case for Annihilating Dark Matter
• Detection of a Gamma-Ray Source in the Galactic Center Consistent with Extended Emission from Dark Matter Annihilation and Concentrated Astrophysical Emission
• Background model systematics for the Fermi GeV excess
• Dark Matter and Pulsar Model Constraints from Galactic Center Fermi-LAT Gamma Ray Observations
• The Fermi Galactic Center GeV Excess and Implications for Dark Matter
• A New $\Sigma -D$ Relation and Its Application to the Galactic Supernova Remnant Distribution
• Fermi-LAT Observations of High-Energy Gamma-Ray Emission Toward the Galactic Center
• Astrophysical and Dark Matter Interpretations of Extended Gamma-Ray Emission from the Galactic Center
• Strong support for the millisecond pulsar origin of the Galactic center GeV excess
• Evidence for Unresolved Gamma-Ray Point Sources in the Inner Galaxy
• Stellar populations in the Milky Way bulge region : Towards solving the Galactic bulge and bar shapes using 2MASS data
• Inverse Compton Origin of the Hard X-Ray and Soft Gamma-Ray Emission from the Galactic Ridge
• Spatial distribution of interstellar gas in the innermost 3 kpc of our Galaxy
• GASS: The Parkes Galactic All-Sky Survey. II. Stray-Radiation Correction and Second Data Release
• A comment on the emission from the Galactic Center as seen by the Fermi telescope
• Revisiting the radial distribution of pulsars 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
• Galactic Bulge Preferred Over Dark Matter for the Galactic Center Gamma-Ray Excess
• Galactic Center gamma-ray "excess" from an active past of the Galactic Centre?
• The Fermi-LAT GeV Excess Traces Stellar Mass in the Galactic Bulge
• Dark Matter Strikes Back at the Galactic Center
• A Global Analysis of Dark Matter Signals from 27 Dwarf Spheroidal Galaxies using 11 Years of Fermi-LAT Observations
• Dark Matter Interpretation of the Fermi-LAT Observation Toward the Galactic Center
• Strong Evidence that the Galactic Bulge is Shining in Gamma Rays
• Foreground Mismodeling and the Point Source Explanation of the Fermi Galactic Center Excess
• The High-Energy Tail of the Galactic Center Gamma-Ray Excess
• Towards a realistic astrophysical interpretation of the gamma-ray Galactic center excess
• A New Mask for An Old Suspect: Testing the Sensitivity of the Galactic Center Excess to the Point Source Mask
• Characterizing the Nature of the Unresolved Point Sources in the Galactic Center
• The GCE in a New Light: Disentangling the $\gamma$-ray Sky with Bayesian Graph Convolutional Neural Networks
• Investigating the Uniformity of the Excess Gamma rays towards the Galactic Center Region
• Hard and bright gamma-ray emission at the base of the Fermi bubbles
• The radial distribution of OB star formation in the Galaxy
• Maximum Entropy Estimation of the Galactic Bulge Morphology via the VVV Red Clump
• Investigating the Fermi Large Area Telescope sensitivity of detecting the characteristics of the Galactic center excess

Cited by in corpus (68)

• Multimessenger constraints on the dark matter interpretation of the Fermi-LAT Galactic center excess
• Celestial-Body Focused Dark Matter Annihilation Throughout the Galaxy
• The Return of the Templates: Revisiting the Galactic Center Excess with Multi-Messenger Observations
• Search for continuous gravitational wave emission from the Milky Way center in O3 LIGO--Virgo data
• Unveiling Hidden Physics at the LHC
• Status and perspectives of Continuous Gravitational Wave searches
• 3D template-based $Fermi$-LAT constraints on the diffuse supernova axion-like particle background
• Exploring dark matter spike distribution around the Galactic centre with stellar orbits
• A neural simulation-based inference approach for characterizing the Galactic Center $\gamma$-ray excess
• Les Houches Lectures on Indirect Detection of Dark Matter
• Dissecting the inner Galaxy with $\gamma$-ray pixel count statistics
• Evidence of TeV Halos Around Millisecond Pulsars
• A Census of X-ray Millisecond Pulsars in Globular Clusters
• Dim but not entirely dark: Extracting the Galactic Center Excess' source-count distribution with neural nets
• Constraining the dark matter contribution of $\gamma$ rays in Cluster of galaxies using Fermi-LAT data
• Prompt cusps and the dark matter annihilation signal
• Luminosity functions consistent with a pulsar-dominated Galactic Center Excess
• Dark Matter Candidates and Searches
• Cherenkov Telescope Array sensitivity to the putative millisecond pulsar population responsible for the Galactic center excess
• The Galactic bulge millisecond pulsars shining in X rays: A gamma-ray perspective
• A Phantom Menace: On the Morphology of the Galactic Center Excess
• Robust inference of the Galactic centre gamma-ray excess spatial properties
• The effect of stellar encounters on the dark matter annihilation signal from prompt cusps
• Fermi LAT observations of Sagittarius A*: Imaging Analysis
• Robustness of the Galactic Center Excess Morphology Against Masking
• Dark matter annihilation and the Galactic Centre Excess
• Constraints on dark matter annihilation from the FAST observation of the Coma Berenices dwarf galaxy
• Muonphilic Dark Matter explanation of gamma-ray galactic center excess: a comprehensive analysis
• Probing the pulsar explanation of the Galactic-Center GeV excess using continuous gravitational-wave searches
• Anomalous Ionization in the Central Molecular Zone by sub-GeV Dark Matter
• Multi-TeV dark matter density in the inner Milky Way halo: spectral and dynamical constraints
• Mind the gap: The discrepancy between simulation and reality drives interpretations of the Galactic Center Excess
• The Andromeda Gamma-Ray Excess: Background Systematics of the Millisecond Pulsars and Dark Matter Interpretations
• Revisiting GeV-scale annihilating dark matter with the AMS-02 positron fraction
• Velocity-dependent annihilation radiation from dark matter subhalos in cosmological simulations
• A New Determination of the Millisecond Pulsar Gamma-Ray Luminosity Function and Implications for the Galactic Center Gamma-Ray Excess
• Towards resolving the Galactic center GeV excess with millisecond-pulsar-like sources using machine learning
• Millisecond Pulsar Kicks Cause Difficulties in Explaining the Galactic Center Gamma-Ray Excess
• Impact of anisotropic cosmic-ray transport on the gamma-ray signatures in the Galactic Center
• Connecting multi-lepton anomalies at the LHC and in Astrophysics with MeerKAT/SKA
• Millisecond Pulsars in Dense Star Clusters: Evolution, Scaling Relations, and the Galactic-Center Gamma-ray Excess
• Late-forming black holes and the antiproton, gamma-ray, and anti-helium excesses
• The Cherenkov Telescope Array Will Test Whether Pulsars Generate the Galactic Center Gamma-Ray Excess
• Applying Simulation-Based Inference to Spectral and Spatial Information from the Galactic Center Gamma-Ray Excess
• Evaluation of the performance of a CdZnTe-based soft $\gamma$-ray detector for CubeSat payloads
• Reconciling Higgs physics and pseudo-Nambu-Goldstone dark matter in the S2HDM using a genetic algorithm
• The effect of kick velocities on the spatial distribution of millisecond pulsars and implications for the Galactic center excess
• Reanalysis of the Systematic Uncertainties in Cosmic-Ray Antiproton Flux
• Detectability of dark matter density distribution via gravitational waves from binary black holes in the Galactic center
• Sub-keV dark matter can strongly ionize molecular clouds
• Einstein@Home Searches for Gamma-ray Pulsars in the Inner Galaxy
• Characterizing the Expected Behavior of Non-Poissonian Template Fitting
• Observations of the Fermi bubbles and the Galactic center excess with the DArk Matter Particle Explorer
• Possible counterpart signal of the Fermi bubbles at the cosmic-ray positrons
• Dark Matter and Electroweak Baryogenesis with Spontaneous $CP$ Violation in the Early Universe
• Rare decays of the $B_s-$meson into four charged leptons in the framework of the Standard Model
• A Fermi-LAT Study of Globular Cluster Dynamical Evolution in the Milky Way: Millisecond Pulsars as the Probe
• Limits on Dark Matter Annihilation from the Shape of Radio Emission in M31
• Millisecond Pulsars in Globular Clusters and Implications for the Galactic Center Gamma-Ray Excess
• On the Energy Distribution of the Galactic Center Excess' Sources
• Assessing the Impact of Hydrogen Absorption on the Characteristics of the Galactic Center Excess
• Combined analyses of the antiproton production from cosmic-ray interactions and its possible dark matter origin
• Analysis of shape and angular orientation parameters of velocity-dependent dark matter annihilation signals in Galactic Centers for FIRE simulations
• Deeper analysis of Fermi-LAT unassociated 4FGL J2112.5-3043 for possible identification
• The potential of diffuse Galactic Ridge neutrino measurements to constrain dark matter
• The contribution to Galactic Centre γ-ray excess from cluster-born millisecond pulsars. Constraints from direct N-body simulations
• The multicomponent dark matter structure and its possible observed manifestations
• Performance Evaluation of a silicon-based 6U Cubesat detector for soft $\gamma$-ray astronomy