Dissecting the inner Galaxy with gamma-ray pixel count statistics

Journal of Physics Conference Series, vol. 2156, pp. 012093

Abstract

Abstract The nature of the GeV gamma-ray Galactic center excess (GCE) in the data of Fermi-LAT is still under investigation. Different techniques, such as template fitting and photon-count statistical methods, have been applied in the past few years in order to disentangle between a GCE coming from sub-threshold point sources or rather from diffuse emissions, such as the dark matter annihilation in the Galactic halo. A major limit to all these studies is the modeling of the Galactic diffuse foreground, and the impact of residual mis-modeled emission on the results’ robustness. We combine for the first time adaptive template fitting and pixel count statistical methods in order to assess the role of sub-threshold point sources to the GCE, while minimizing the mis-modelling of diffuse emission components. We reconstruct the flux distribution of point sources in the inner Galaxy well below the Fermi-LAT detection threshold, and measure their radial and longitudinal profiles. We find that point sources and diffuse emission from the Galactic bulge each contributes about 10% of the total emission therein, disclosing a potential sub-threshold point-source contribution to the GCE.

Authors 3

1. Silvia Manconi corresponding Aachen Speaker Institut fur Theoretische Teilchenphysik und Kosmologie

   RWTH Aachen University

   Affiliation as printed

   Speaker, Institut fur Theoretische Teilchenphysik und Kosmologie, RWTH Aachen University, Germany

2. Francesca Calore

   Centre National de la Recherche Scientifique · Université Grenoble Alpes · Laboratoire d'Annecy de Physique Théorique

   Affiliation as printed

   Univ. Grenoble Alpes, USMB, CNRS, LAPTh, F-74940 Annecy, France

3. Fiorenza Donato

   Istituto Nazionale di Fisica Nucleare, Sezione di Torino

   Affiliation as printed

   Dipartimento di Fisica, Universita di Torino and Istituto Nazionale di Fisica Nucleare, Sezione di Torino, via P. Giuria, 1, I-10125 Torino, Italy