Foreground mismodeling and the point source explanation of the Fermi Galactic Center excess

Buschmann, Malte; Rodd, Nicholas L.; Safdi, Benjamin R.; Chang, Luke L. Y.; Mishra-Sharma, Siddharth; Lisanti, Mariangela; Macías, Óscar

doi:10.1103/physrevd.102.023023

Cited by 83 publications

(121 citation statements)

References 67 publications

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“…Reference [15] showed in detail that there are important morphological differences between the interpolated and hydrodynamic gas maps and that the latter provides a significantly better fit to the gamma-ray data in the GC region. Note that this result has been independently confirmed with the non-Poissonian template fitting pipeline [49].…”

Section: Appendix A: Methodssupporting

confidence: 63%

“…While this will not quantitatively change our constraints, it will provide corroborating evidence for the bulge-GCE connection that our analysis clearly prefers. This may be possible through the non-Poissonian template fitting procedure [44][45][46][47][48][49] and wavelet techniques [50][51][52] to detect clustering of photons or radio detection of point sources responsible for the bulge emission [41] or detection of a significant number of millisecond pulsars (putative sources for the bulge gamma-ray emission) with radio telescopes [53][54][55][56].…”

Section: Figmentioning

confidence: 99%

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Strong constraints on thermal relic dark matter from Fermi-LAT observations of the Galactic Center

et al. 2020

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The extended excess toward the Galactic Center (GC) in gamma rays inferred from Fermi-LAT observations has been interpreted as being due to dark matter (DM) annihilation. Here, we perform new likelihood analyses of the GC and show that, when including templates for the stellar galactic and nuclear bulges, the GC shows no significant detection of a DM annihilation template, even after generous variations in the Galactic diffuse emission models and a wide range of DM halo profiles. We include Galactic diffuse emission models with combinations of three-dimensional inverse Compton maps, variations of interstellar gas maps, and a central source of electrons. For the DM profile, we include both spherical and ellipsoidal DM morphologies and a range of radial profiles from steep cusps to kiloparsec-sized cores, motivated in part by hydrodynamical simulations. Our derived upper limits on the dark matter annihilation flux place strong constraints on DM properties. In the case of the pure b-quark annihilation channel, our limits on the annihilation cross section are more stringent than those from the Milky Way dwarfs up to DM masses of approximately TeV and rule out the thermal relic cross section up to approximately 300 GeV. Better understanding of the DM profile, as well as the Fermi-LAT data at its highest energies, would further improve the sensitivity to DM properties.

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Section: Appendix A: Methodssupporting

confidence: 63%

Section: Figmentioning

confidence: 99%

Strong constraints on thermal relic dark matter from Fermi-LAT observations of the Galactic Center

et al. 2020

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“…Gamma-rays can be produced in point sources but also as a diffuse glow by electron bremsstrahlung, by inverse Compton scattering of electrons and positrons on the intense ambient radiation field in the region, or as products of the interactions of cosmic-rays with the interstellar gas. The calculation of the expected gamma-ray flux from all these processes, along with the galactic model used to track the diffusion of cosmic-rays in their way through the galaxy, is plagued with uncertainties which reflect in the predicted gamma ray emission from the Galactic Centre (which is the background when searching for dark matter) [134][135][136][137]. Indeed the EGRET excess was promptly explained by detailed calculations of the expected cosmic-ray flux without the need of new physics [138].…”

Section: Gamma-and X-raysmentioning

confidence: 99%

Status, Challenges and Directions in Indirect Dark Matter Searches

Heros

2020

Symmetry

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Indirect searches for dark matter are based on detecting an anomalous flux of photons, neutrinos or cosmic-rays produced in annihilations or decays of dark matter candidates gravitationally accumulated in heavy cosmological objects, like galaxies, the Sun or the Earth. Additionally, evidence for dark matter that can also be understood as indirect can be obtained from early universe probes, like fluctuations of the cosmic microwave background temperature, the primordial abundance of light elements or the Hydrogen 21-cm line. The techniques needed to detect these different signatures require very different types of detectors: Air shower arrays, gamma- and X-ray telescopes, neutrino telescopes, radio telescopes or particle detectors in balloons or satellites. While many of these detectors were not originally intended to search for dark matter, they have proven to be unique complementary tools for direct search efforts. In this review we summarize the current status of indirect searches for dark matter, mentioning also the challenges and limitations that these techniques encounter.

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“…[56] can misattribute smooth gamma-ray signals (such as that predicted from annihilating dark matter) to point source populations. While it was recently shown that this in part was likely due to mismodeling of the diffuse model [138], more serious issues with this technique have been identified [139,140]. It has been shown that systematics arising from mismodeling give rise to spurious point source evidence for the GCE, and once correcting for this systematic, the evidence for point sources disappears [139,140].…”

Section: The Galactic Center Gamma-ray Excessmentioning

confidence: 99%

A systematic study of hidden sector dark matter: application to the gamma-ray and antiproton excesses

Leane

Tsai

Wegsman

et al. 2020

J. High Energ. Phys.

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In hidden sector models, dark matter does not directly couple to the particle content of the Standard Model, strongly suppressing rates at direct detection experiments, while still allowing for large signals from annihilation. In this paper, we conduct an extensive study of hidden sector dark matter, covering a wide range of dark matter spins, mediator spins, interaction diagrams, and annihilation final states, in each case determining whether the annihilations are s-wave (thus enabling efficient annihilation in the universe today). We then go on to consider a variety of portal interactions that allow the hidden sector annihilation products to decay into the Standard Model. We broadly classify constraints from relic density requirements and dwarf spheroidal galaxy observations. In the scenario that the hidden sector was in equilibrium with the Standard Model in the early universe, we place a lower bound on the portal coupling, as well as on the dark matter's elastic scattering cross section with nuclei. We apply our hidden sector results to the observed Galactic Center gamma-ray excess and the cosmic-ray antiproton excess. We find that both of these excesses can be simultaneously explained by a variety of hidden sector models, without any tension with constraints from observations of dwarf spheroidal galaxies.

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Foreground mismodeling and the point source explanation of the Fermi Galactic Center excess

Cited by 83 publications

References 67 publications

Strong constraints on thermal relic dark matter from Fermi-LAT observations of the Galactic Center

Strong constraints on thermal relic dark matter from Fermi-LAT observations of the Galactic Center

Status, Challenges and Directions in Indirect Dark Matter Searches

A systematic study of hidden sector dark matter: application to the gamma-ray and antiproton excesses

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