Towards resolving the Galactic center GeV excess with millisecond-pulsar-like sources using machine learning

Abstract

Excess of gamma rays around the Galactic center (GC) observed in the Fermi Large Area Telescope (LAT) data is one of the most intriguing features in the gamma-ray sky. The spherical morphology and the spectral energy distribution with a peak around a few GeV are consistent with emission from annihilation of dark matter particles. Other possible explanations include a distribution of millisecond pulsars (MSPs). One of the caveats of the MSP hypothesis is the relatively small number of associated MSPs near the GC. In this paper, we perform a multiclass classification of Fermi-LAT sources using machine learning and determine the contribution from unassociated MSP-like sources near the GC. The spectral energy distribution, spatial morphology, and the source count distribution are consistent with expectations for a population of MSPs that can explain the gamma-ray excess. Possible caveats of the contribution from the unassociated MSP-like sources are discussed.

14 pages, 13 figures, 4 tables, v2: references and discussions added, v3: published version, probabilistic classification of sources is available online at https://zenodo.org/doi/10.5281/zenodo.10458463

References in corpus (52)

• Astropy: A Community Python Package for Astronomy
• Fermi Large Area Telescope Fourth Source Catalog
• Dark Matter Annihilation in The Galactic Center As Seen by the Fermi Gamma Ray Space Telescope
• Incremental Fermi Large Area Telescope Fourth Source Catalog
• On The Origin Of The Gamma Rays From The Galactic Center
• 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
• Fermi-LAT Observations of High-Energy Gamma-Ray Emission Toward 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
• The Consistency of Fermi-LAT Observations of the Galactic Center with a Millisecond Pulsar Population in the Central Stellar Cluster
• Galactic Bulge Preferred Over Dark Matter for the Galactic Center Gamma-Ray Excess
• Disrupted Globular Clusters Can Explain 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
• The Galactic Center GeV Excess from a Series of Leptonic Cosmic-Ray Outbursts
• The characteristics of the Galactic center excess measured with 11 years of Fermi-LAT data
• The Fermi-LAT GeV Excess Traces Stellar Mass in the Galactic Bulge
• Dark Matter Strikes Back at 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
• Radio detection prospects for a bulge population of millisecond pulsars as suggested by Fermi LAT observations of the inner Galaxy
• The Return of the Templates: Revisiting the Galactic Center Excess with Multi-Messenger Observations
• Spurious Point Source Signals in the Galactic Center Excess
• The Gamma-Ray Pulsar Population of Globular Clusters: Implications for the GeV Excess
• The Enigmatic Galactic Center Excess: Spurious Point Sources and Signal Mismodeling
• 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
• Distinguishing Dark Matter from Unresolved Point Sources in the Inner Galaxy with Photon Statistics
• Low Mass X-Ray Binaries in the Inner Galaxy: Implications for Millisecond Pulsars and the GeV Excess
• The GCE in a New Light: Disentangling the $\gamma$-ray Sky with Bayesian Graph Convolutional Neural Networks
• Millisecond Pulsars from Accretion Induced Collapse as the Origin of the Galactic Centre Gamma-ray Excess Signal
• A neural simulation-based inference approach for characterizing the Galactic Center $\gamma$-ray excess
• Bayesian Model Comparison and Analysis of the Galactic Disk Population of Gamma-Ray Millisecond Pulsars
• Population syntheses of millisecond pulsars from the Galactic Disk and Bulge
• Dissecting the inner Galaxy with $\gamma$-ray pixel count statistics
• An investigation on the factors affecting machine learning classifications in $\gamma$-ray astronomy
• Putting Things Back Where They Belong: Tracing Cosmic-Ray Injection with H2
• Comparing the Galactic Bulge and Galactic Disk Millisecond Pulsars
• Dim but not entirely dark: Extracting the Galactic Center Excess' source-count distribution with neural nets
• Classification of Fermi-LAT sources with deep learning using energy and time spectra
• Searching for AGN and Pulsar Candidates in 4FGL Unassociated Sources Using Machine Learning
• A Phantom Menace: On the Morphology of the Galactic Center Excess
• Robust inference of the Galactic centre gamma-ray excess spatial properties
• Machine learning methods for constructing probabilistic Fermi-LAT catalogs
• Robustness of the Galactic Center Excess Morphology Against Masking
• Multi-class classification of Fermi-LAT sources with hierarchical class definition
• Mind the gap: The discrepancy between simulation and reality drives interpretations of the Galactic Center Excess
• Effect of covariate shift on multi-class classification of Fermi-LAT sources

Cited by in corpus (5)

• Einstein@Home Searches for Gamma-ray Pulsars in the Inner Galaxy
• On the Energy Distribution of the Galactic Center Excess' Sources
• Millisecond Pulsars in Globular Clusters and Implications for the Galactic Center Gamma-Ray Excess
• Exploring the nature of Galactic unassociated sources detected by the Fermi-LAT
• Classification of Fermi-LAT unassociated sources with machine learning in the presence of dataset shifts