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The Galactic Center Excess (GCE) remains an enduring mystery, with leading explanations being annihilating dark matter or an unresolved population of millisecond pulsars. Analyzing the morphology of the GCE provides critical clues to…

High Energy Astrophysical Phenomena · Physics 2024-06-13 Yi-Ming Zhong , Ilias Cholis

The Galactic Centre {\gamma}-ray excess (GCE), observed by Fermi-LAT around Sgr A*, exceeds expectations from standard cosmic-ray models and is commonly attributed either to dark matter annihilation or to unresolved millisecond pulsars…

High Energy Astrophysical Phenomena · Physics 2026-04-02 M. Kalambay , M. Ishchenko , D. Kuvatova , T. Panamarev , P. Berczik

Gamma-ray data from the Fermi-Large Area Telescope reveal an unexplained, apparently diffuse, signal from the Galactic bulge that peaks near 2 GeV with an approximately spherical intensity profile $\propto r^{-2.4}$ that extends to angular…

High Energy Astrophysical Phenomena · Physics 2022-05-03 Anuj Gautam , Roland M. Crocker , Lilia Ferrario , Ashley J. Ruiter , Harrison Ploeg , Chris Gordon , Oscar Macias

We present a potential test of the origin of the $\gamma$-ray Galactic Centre Excess (GCE). We demonstrate how gravitational microlensing by stellar mass objects along the line of sight to the Galactic Bulge can distinguish between the…

High Energy Astrophysical Phenomena · Physics 2025-08-28 Nada Salama , Florian List , Geraint Lewis

The Galactic Center Excess (GCE) is a compelling signature of dark matter annihilation, but its spectral morphology is difficult to reconcile with the traditional paradigm of a single particle species. In this work, we perform a systematic…

High Energy Physics - Phenomenology · Physics 2026-03-19 Farinaldo S. Queiroz , Clarissa Siqueira , Carlos E. Yaguna

This paper reports that the X-ray spectrum from the Galactic Center X-ray Emission (GCXE) is expressed by the assembly of active binaries, non-magnetic Cataclysmic Variables, magnetic Cataclysmic Variables (X-ray active star: XAS), cold…

High Energy Astrophysical Phenomena · Physics 2021-09-01 Masayoshi Nobukawa , Katsuji Koyama

We have performed a systematic study of the statistical behavior of non-Poissonian template fitting (NPTF), a method designed to analyze and characterize unresolved point sources in general counts datasets. In this paper, we focus on the…

Instrumentation and Methods for Astrophysics · Physics 2023-05-24 Luis Gabriel C. Bariuan , Tracy R. Slatyer

We present NPTFit, an open-source code package, written in python and cython, for performing non-Poissonian template fits (NPTFs). The NPTF is a recently-developed statistical procedure for characterizing the contribution of unresolved…

High Energy Astrophysical Phenomena · Physics 2017-06-07 Siddharth Mishra-Sharma , Nicholas L. Rodd , Benjamin R. Safdi

The characteristics of the Galactic Center Excess (GCE) emission observed in gamma-ray energies -- especially the morphology of the GCE -- remain a hotly debated subject. The manner in which the dominant diffuse gamma-ray background is…

High Energy Astrophysical Phenomena · Physics 2023-10-10 Samuel D. McDermott , Yi-Ming Zhong , Ilias Cholis

The Galactic Center Excess (GCE) is an extended gamma-ray source in the central region of the Galaxy found in Fermi Large Area Telescope (Fermi-LAT) data. One of the leading explanations for the GCE is an unresolved population of…

High Energy Astrophysical Phenomena · Physics 2021-06-15 Harrison Ploeg , Chris Gordon , Roland Crocker , Oscar Macias

Recent analyses of the anisotropy of cosmic rays at $10^{18}$ eV (the AGASA and SUGAR data) show significant excesses from regions close to the Galactic Centre and Cygnus. Our aim is to check whether such anisotropies can be caused by…

Astrophysics · Physics 2008-11-26 W. Bednarek , M. Giller , M. Zielinska

We present a new method to characterize unresolved point sources (PSs), generalizing traditional template fits to account for non-Poissonian photon statistics. We apply this method to Fermi Large Area Telescope gamma-ray data to…

High Energy Astrophysical Phenomena · Physics 2016-02-10 Samuel K. Lee , Mariangela Lisanti , Benjamin R. Safdi , Tracy R. Slatyer , Wei Xue

An anomalous gamma-ray excess emission has been found in Fermi Large Area Telescope data covering the centre of the Galaxy. Several theories have been proposed for this `Galactic Centre Excess'. They include self-annihilation of dark matter…

High Energy Astrophysical Phenomena · Physics 2023-08-10 Oscar Macias , Chris Gordon , Roland M. Crocker , Brenna Coleman , Dylan Paterson , Shunsaku Horiuchi , Martin Pohl

Excess of gamma rays with a spherical morphology 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 excess has been interpreted by…

High Energy Astrophysical Phenomena · Physics 2024-06-07 Dmitry V. Malyshev

Millisecond pulsars (MSPs) are a leading explanation of the Galactic Center excess (GCE) observed in Fermi-LAT data. We constrain this scenario by jointly modeling prompt and inverse-Compton $\gamma$ rays from MSP-injected $e^\pm$ on the…

High Energy Astrophysical Phenomena · Physics 2026-05-27 Jordan Koechler , Pedro De la Torre Luque , Mattia Di Mauro

The identification and description of point sources is one of the oldest problems in astronomy; yet, even today the correct statistical treatment for point sources remains one of the field's hardest problems. For dim or crowded sources,…

Instrumentation and Methods for Astrophysics · Physics 2022-06-29 Gabriel H. Collin , Nicholas L. Rodd , Tyler Erjavec , Kerstin Perez

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…

High Energy Astrophysical Phenomena · Physics 2015-12-09 Ilias Cholis , Carmelo Evoli , Francesca Calore , Tim Linden , Christoph Weniger , Dan Hooper

The Galactic Center Gamma-Ray Excess has a spectrum, angular distribution, and overall intensity that agree remarkably well with that expected from annihilating dark matter particles in the form of a $m_X \sim 50 \, {\rm GeV}$ thermal…

High Energy Astrophysical Phenomena · Physics 2022-09-30 Dan Hooper

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…

High Energy Astrophysical Phenomena · Physics 2025-03-13 Dmitry V. Malyshev

The Fermi Large Area Telescope has provided the most detailed view toward the Galactic Centre (GC) in high-energy gamma rays. Besides the interstellar emission and point-source contributions, the data suggest a residual diffuse gamma-ray…

Astrophysics of Galaxies · Physics 2018-02-07 Giacomo Fragione , Fabio Antonini , Oleg Y. Gnedin