Cherenkov Telescope Array Sensitivity to the Putative Millisecond Pulsar Population responsible for the Galactic Center Excess

Abstract:

Past studies of the Fermi Galactic Center Excess (GCE) have found evidence for a "high-energy tail" in the GCE spectrum. Such a signature could be the result of inverse-Compton (IC) gamma rays produced by the injection of electrons/positrons into the interstellar medium by the putative population of millisecond pulsar (MSPs) responsible for the GCE.  For this ICRC 2021 contribution, we present the results of an exhaustive study on simulated data, in which we analyze the detection potential of the forthcoming Cherenkov Telescope Array (CTA) to the high-energy tail of the GCE. In particular, we find that CTA will have sufficient sensitivity to detect this signal for physically reasonable electron/positron acceleration efficiencies, provided that the Galactic diffuse emission model (GDE) is well understood. Furthermore, we discuss the necessary conditions for a reliable CTA discovery in the case of a high degree of uncertainties in the GDE model. We also show that in the event that CTA observes an excess of  diffuse gamma rays in the Galactic bulge, it will be able to discriminate between the dark matter and MSPs hypotheses, based on their distinct spatial morphologies.

Executive Summary

Authors: Oscar Macias

Co-Authors: Harm van Leijen | Deheng Song | Shin'ichiro Ando | Shunsaku Horiuchi | Roland Crocker
Indico-ID: 110
Proceeding URL: https://pos.sissa.it/395/562

Discussion timeslot (ZOOM-Meeting): 21. July 2021 - 12:00
ZOOM-Meeting URL: https://desy.zoom.us/j/91999581729
ZOOM-Meeting ID: 91999581729
ZOOM-Meeting Passcode: ICRC2021
Corresponding Session: https://icrc2021-venue.desy.de/channel/41-Indirect-Dark-Matter-Detection-Through-Photons-and-Neutrinos-DM/95
Live-Stream URL: https://icrc2021-venue.desy.de/livestream/Discussion-05/6