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Stellarlike Galactic Center excess challenges particle dark matter

Silvia Manconi1,2,*, Christopher Eckner3,†, Francesca Calore2,‡, and Fiorenza Donato4,5,§

  • *Contact author: manconi@lpthe.jussieu.fr
  • †Contact author: ceckner@ung.si
  • ‡Contact author: calore@lapth.cnrs.fr
  • §Contact author: fiorenza.donato@unito.it
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Phys. Rev. D 114, 043053 – Published 20 August, 2026

DOI: https://doi.org/10.1103/2wkq-xrsc

Abstract

The Galactic Center is potentially hosting the largest indirect signal from particle dark matter (DM), which in many well-motivated models would produce gamma rays as their final states. However, this region has often been dismissed for DM studies because of the evidence for an unexpected gamma-ray component over astrophysical backgrounds at GeV energies, firstly discovered in the data of the Fermi Large Area Telescope (LAT), the so-called Galactic Center excess (GCE). While this was initially considered to hint at GeV thermal relics, recent work supports a GCE interpretation in terms of a stellar population of millisecond pulsarlike sources in the Galactic bulge. Building on this preference, we reevaluate the Galactic Center as a powerful target for indirect DM searches via gamma rays. This is achieved by combining adaptive template fitting and photon-count statistical methods to assess the role of subthreshold point sources in the observed Fermi-LAT gamma-ray counts while minimizing the mismodeling of Galactic diffuse-emission backgrounds. In a fully self-consistent way, the gamma-ray data are fitted with a mixed model comprising a DM signal and a stellar bulge, both potentially contributing to the GCE. The space left for signals from weak-scale DM particle annihilations is quantified by extracting 95% confidence level upper limits on the annihilation cross section, which, depending on the DM density profile, result in stringent limits for masses ≲300  GeV. The robustness of our results is supported by tests on simulated data.

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Phys. Rev. D 114, 043053– Published 20 August, 2026
  • Received 18 November 2025
  • Accepted 14 July 2026
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