Dark matter annihilation in the Galactic Center as seen by the Fermi Gamma Ray Space Telescope

By D. Hooper, L. Goodenough. 2010

746 citations recorded by the source corpus.

Abstract We analyze the first two years of data from the Fermi Gamma Ray Space Telescope from the direction of the inner 10° around the Galactic Center with the intention of constraining, or finding evidence of, annihilating dark matter. We find that the morphology and spectrum of the emission between 1.25° and 10° from the Galactic Center is well described by the processes of decaying pions produced in cosmic ray collisions with gas, and the inverse Compton scattering of cosmic ray electrons in both the disk and bulge of the Inner Galaxy, along with gamma rays from known points sources in the region. The observed spectrum and morphology of the emission within approximately 1.25° (∼175 parsecs) of the Galactic Center, in contrast, departs from the expectations for by these processes. Instead, we find an additional component of gamma ray emission that is highly concentrated around the Galactic Center. The observed morphology of this component is consistent with that predicted from annihilating dark matter with a cusped (and possibly adiabatically contracted) halo distribution ( ρ ∝ r − γ , with γ = 1.18 to 1.33). The observed spectrum of this component, which peaks at energies between 1–4 GeV (in E 2 units), can be well fit by a 7–10 GeV dark matter particle annihilating primarily to tau leptons with a cross section in the range of 〈 σ v 〉 = 4.6 × 10 − 27 to 5.3 × 10 − 26 cm 3 / s , depending on how the dark matter distribution is normalized. We also discuss other sources for this emission, including the possibility that much of it originates from the Milky Wayʼs supermassive black hole.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/079c74d581e6d95785a4ac51ae2cb03213b9c0f4

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Citations in the corpus

A White Paper on keV sterile neutrino Dark Matter (2016, background): “The search for the identity of the Dark Matter is currently at a very exciting stage, with tentative, mutually exclusive, claims for detections of CDM [415] and WDM [190].”
WIMP dark matter candidates and searches—current status and future prospects (2017, background): “The annihilation cross section was reported as 2–3 × 10−26 cm3 s−1 [285] for bb̄ and 7–9 × 10−27 cm3 s−1 for τ+τ− [280] final states which are remarkably similar to the annihilation cross section required for a thermal relic.”
Gravitational probes of dark matter physics (2017, background): “Indirect detection searches for dark matter annihilation or decay in the Universe today can improve signal over background by targeting high-density regions — be it the Galactic Center [441, 442, 443, 444, 445, 446, 447, 448, 449, 450, 451, 452, 453, 454, 455, 456], satellite galaxies [457, 458, 459”
The Fermi Galactic Center GeV Excess and Implications for Dark Matter (2017, background): “…the GC on top of a variety of models for interstellar gamma-ray emission and point sources (PSs; e.g., Goodenough & Hooper 2009; Vitale et al. 2009; Hooper & Goodenough 2011; Abazajian & Kaplinghat 2012; Gordon & Macías 2013; Hooper & Slatyer 2013; Calore et al. 2015; Zhou et al. 2015; Ajello et…”
The Consistency of Fermi-LAT Observations of the Galactic Center with a Millisecond Pulsar Population in the Central Stellar Cluster (2010, methodology): “ Introduction The ability of gamma-ray observatories to provide a window on dark matter annihilation signals has been known for some time, (e.g. [1]). The recent manuscript by Hooper & Goodenough [2] performs a detailed analysis to extract the signal in the gamma-ray of the dynamical center of o”
Gamma Ray Signals from Dark Matter: Concepts, Status and Prospects (2012, background): “, they correspond to DM masses in the ∼MeV [209–211], ∼10 GeV [185, 212, 213], ∼100 GeV [214], ∼TeV [61, 215–217] (sometimes with possible counterparts at radio frequencies [218–220]) or even multi-TeV range [221–223].”
Toward (finally!) ruling out Z and Higgs mediated dark matter models (2016, background): “In the currently allowed mass range near the Higgs pole, this class of models predicts a very small low-velocity annihilation cross section, which is likely unable to generate the measured intensity of the Galactic Center gamma-ray excess [42–48] (see also, Refs.”