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Title: The Fermi Galactic Center GeV Excess and Implications for Dark Matter

Abstract

The region around the Galactic Center (GC) is now well established to be brighter at energies of a few GeV than what is expected from conventional models of diffuse gamma-ray emission and catalogs of known gamma-ray sources. We study the GeV excess using 6.5 yr of data from the Fermi Large Area Telescope. We characterize the uncertainty of the GC excess spectrum and morphology due to uncertainties in cosmic-ray source distributions and propagation, uncertainties in the distribution of interstellar gas in the Milky Way, and uncertainties due to a potential contribution from the Fermi bubbles. We also evaluate uncertainties in the excess properties due to resolved point sources of gamma rays. The GC is of particular interest, as it would be expected to have the brightest signal from annihilation of weakly interacting massive dark matter (DM) particles. However, control regions along the Galactic plane, where a DM signal is not expected, show excesses of similar amplitude relative to the local background. Based on the magnitude of the systematic uncertainties, we conservatively report upper limits for the annihilation cross-section as a function of particle mass and annihilation channel.

Authors:
;  [1];  [2];  [3];  [4];  [5];  [6];  [7];  [8];  [9];  [10]; ; ;  [11];  [12];  [13];  [14];  [15];
  1. Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen (Germany)
  2. Department of Physics and Astronomy, Clemson University, Kinard Lab of Physics, Clemson, SC 29634-0978 (United States)
  3. Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
  4. Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States)
  5. Università di Pisa and Istituto Nazionale di Fisica Nucleare, Sezione di Pisa I-56127 Pisa (Italy)
  6. Laboratoire AIM, CEA-IRFU/CNRS/Université Paris Diderot, Service d’Astrophysique, CEA Saclay, F-91191 Gif sur Yvette (France)
  7. Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy)
  8. Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy)
  9. Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy)
  10. Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari (Italy)
  11. W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)
  12. Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino (Italy)
  13. NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  14. Laboratoire Univers et Particules de Montpellier, Université Montpellier, CNRS/IN2P3, F-34095 Montpellier (France)
  15. Laboratoire Leprince-Ringuet, École polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France)
Publication Date:
OSTI Identifier:
22663644
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 840; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLITUDES; ANNIHILATION; CATALOGS; COSMIC GAMMA SOURCES; COSMIC RADIATION; CROSS SECTIONS; DISTRIBUTION; EMISSION; GAMMA RADIATION; GAMMA SOURCES; GEV RANGE; MASS; MILKY WAY; NONLUMINOUS MATTER; SPECTRA; TELESCOPES

Citation Formats

Ackermann, M., Buehler, R., Ajello, M., Albert, A., Atwood, W. B., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bellazzini, R., Bissaldi, E., Blandford, R. D., Bloom, E. D., Bottacini, E., Bonino, R., Brandt, T. J., Bregeon, J., Bruel, P., Collaboration:, and others, and. The Fermi Galactic Center GeV Excess and Implications for Dark Matter. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA6CAB.
Ackermann, M., Buehler, R., Ajello, M., Albert, A., Atwood, W. B., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bellazzini, R., Bissaldi, E., Blandford, R. D., Bloom, E. D., Bottacini, E., Bonino, R., Brandt, T. J., Bregeon, J., Bruel, P., Collaboration:, & others, and. The Fermi Galactic Center GeV Excess and Implications for Dark Matter. United States. doi:10.3847/1538-4357/AA6CAB.
Ackermann, M., Buehler, R., Ajello, M., Albert, A., Atwood, W. B., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bellazzini, R., Bissaldi, E., Blandford, R. D., Bloom, E. D., Bottacini, E., Bonino, R., Brandt, T. J., Bregeon, J., Bruel, P., Collaboration:, and others, and. Mon . "The Fermi Galactic Center GeV Excess and Implications for Dark Matter". United States. doi:10.3847/1538-4357/AA6CAB.
@article{osti_22663644,
title = {The Fermi Galactic Center GeV Excess and Implications for Dark Matter},
author = {Ackermann, M. and Buehler, R. and Ajello, M. and Albert, A. and Atwood, W. B. and Baldini, L. and Ballet, J. and Barbiellini, G. and Bastieri, D. and Bellazzini, R. and Bissaldi, E. and Blandford, R. D. and Bloom, E. D. and Bottacini, E. and Bonino, R. and Brandt, T. J. and Bregeon, J. and Bruel, P. and Collaboration: and others, and},
abstractNote = {The region around the Galactic Center (GC) is now well established to be brighter at energies of a few GeV than what is expected from conventional models of diffuse gamma-ray emission and catalogs of known gamma-ray sources. We study the GeV excess using 6.5 yr of data from the Fermi Large Area Telescope. We characterize the uncertainty of the GC excess spectrum and morphology due to uncertainties in cosmic-ray source distributions and propagation, uncertainties in the distribution of interstellar gas in the Milky Way, and uncertainties due to a potential contribution from the Fermi bubbles. We also evaluate uncertainties in the excess properties due to resolved point sources of gamma rays. The GC is of particular interest, as it would be expected to have the brightest signal from annihilation of weakly interacting massive dark matter (DM) particles. However, control regions along the Galactic plane, where a DM signal is not expected, show excesses of similar amplitude relative to the local background. Based on the magnitude of the systematic uncertainties, we conservatively report upper limits for the annihilation cross-section as a function of particle mass and annihilation channel.},
doi = {10.3847/1538-4357/AA6CAB},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 840,
place = {United States},
year = {2017},
month = {5}
}

Works referencing / citing this record:

The first catalog of Fermi -LAT sources below 100 MeV
journal, October 2018


Search for γ -ray emission from dark matter particle interactions from the Andromeda and Triangulum galaxies with the Fermi Large Area Telescope
journal, June 2019


Novel gamma-ray signatures of PeV-scale dark matter
journal, April 2018

  • Blanco, Carlos; Harding, J. Patrick; Hooper, Dan
  • Journal of Cosmology and Astroparticle Physics, Vol. 2018, Issue 04
  • DOI: 10.1088/1475-7516/2018/04/060

On the dissection of degenerate cosmologies with machine learning
journal, April 2019

  • Merten, Julian; Giocoli, Carlo; Baldi, Marco
  • Monthly Notices of the Royal Astronomical Society, Vol. 487, Issue 1
  • DOI: 10.1093/mnras/stz972