Constraining the dark matter annihilation cross-section with Cherenkov telescope observations of dwarf galaxies

Pieri, L.; Lattanzi, M.; Silk, Joseph

doi:10.1111/j.1365-2966.2009.15388.x

Cited by 39 publications

(44 citation statements)

References 64 publications

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“…Such astrophysical enhancements, combined with particle physics enhancements, have been proposed as an explanation for the cosmic ray lepton anomalies [43,52,53]. Finally, decaying dark matter models have also been suggested to explain the lepton excesses and are good alternatives to annihilating dark matter models [54][55][56][57][58].…”

Section: Introductionmentioning

confidence: 99%

VERITAS deep observations of the dwarf spheroidal galaxy Segue 1

Aliu¹,

Archambault²,

Arlen³

et al. 2012

Phys. Rev. D

104

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The VERITAS array of Cherenkov telescopes has carried out a deep observational program on the nearby dwarf spheroidal galaxy Segue 1. We report on the results of nearly 48 hours of good quality selected data, taken between January 2010 and May 2011. No significant γ-ray emission is detected at the nominal position of Segue 1, and upper limits on the integrated flux are derived. According to recent studies, Segue 1 is the most dark matter-dominated dwarf spheroidal galaxy currently known. We derive stringent bounds on various annihilating and decaying dark matter particle models. The upper limits on the velocity-weighted annihilation cross-section are σv 95% CL < ∼ 10 −23 cm 3 s −1 , improving our limits from previous observations of dwarf spheroidal galaxies by at least a factor of two for dark matter particle masses m χ > ∼ 300 GeV. The lower limits on the decay lifetime are at the level of τ 95% CL > ∼ 10 24 s. Finally, we address the interpretation of the cosmic ray lepton anomalies measured by ATIC and PAMELA in terms of dark matter annihilation, and show that the VERITAS observations of Segue 1 disfavor such a scenario.

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Section: Introductionmentioning

confidence: 99%

VERITAS deep observations of the dwarf spheroidal galaxy Segue 1

Aliu¹,

Archambault²,

Arlen³

et al. 2012

Phys. Rev. D

104

View full text Add to dashboard Cite

show abstract

“…Effectively this increases the value of the integral in Equation (4), especially for the higher mass neutralino models. In addition, the σ v for self-annihilation at the present cosmological time may be considerably larger than at the time of WIMP decoupling due to a velocity-dependent term in the cross section and the reduction of the kinetic energy of the WIMP due to the cosmological expansion of the universe (Robertson & Zentner 2009;Pieri et al 2009). …”

Section: Limits On Wimp Parameter Spacementioning

confidence: 99%

Veritas Search for Vhe Gamma-Ray Emission From Dwarf Spheroidal Galaxies

Acciari

Arlen

Aune

et al. 2010

ApJ

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Indirect dark matter searches with ground-based gamma-ray observatories provide an alternative for identifying the particle nature of dark matter that is complementary to that of direct search or accelerator production experiments. We present the results of observations of the dwarf spheroidal galaxies Draco, Ursa Minor, Boötes 1, and Willman 1 conducted by the Very Energetic Radiation Imaging Telescope Array System (VERITAS). These galaxies are nearby dark matter dominated objects located at a typical distance of several tens of kiloparsecs for which there are good measurements of the dark matter density profile from stellar velocity measurements. Since the conventional astrophysical background of very high energy gamma rays from these objects appears to be negligible, they are good targets to search for the secondary gamma-ray photons produced by interacting or decaying dark matter particles. No significant gamma-ray flux above 200 GeV was detected from these four dwarf galaxies for a typical exposure of ∼20 hr. The 95% confidence upper limits on the integral gamma-ray flux are in the range (0.4-2.2) × 10 −12 photons cm −2 s −1 . We interpret this limiting flux in the context of pair annihilation of weakly interacting massive particles (WIMPs) and derive constraints on the thermally averaged product of the total self-annihilation cross section and the relative velocity of the WIMPs ( σ v 10 −23 cm 3 s −1 for m χ 300 GeV c −2 ). This limit is obtained under conservative assumptions regarding the dark matter distribution in dwarf galaxies and is approximately 3 orders of magnitude above the generic theoretical prediction for WIMPs in the minimal supersymmetric standard model framework. However, significant uncertainty exists in the dark matter distribution as well as the neutralino cross sections which under favorable assumptions could further lower this limit.

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“…The annihilation signal coming from Draco has been the subject of much research in recent years because of its relative proximity to the Earth [65,110,144,146,147,148,149,150]. The prospects for DM annihilation detection from dSphs has in general been found to be rather poor, with detection with Fermi being unlikely [150,151]. Some of the dSphs have already been the subject of observational searches for DM annihilation and some limits on the DM annihilation signal have already been set [152,153,154,155,156,157].…”

Section: Predicted Annihilation Signals For Dwarf Spheroidalsmentioning

confidence: 99%

Substructure boosts to dark matter annihilation from Sommerfeld enhancement

Bovy

2009

Phys. Rev. D

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The recently introduced Sommerfeld enhancement of the dark matter annihilation cross section has important implications for the detection of dark matter annihilation in subhalos in the Galactic halo. In addition to the boost to the dark matter annihilation cross section from the high densities of these subhalos with respect to the main halo, an additional boost caused by the Sommerfeld enhancement results from the fact that they are kinematically colder than the Galactic halo. If we further believe the generic prediction of CDM that in each subhalo there is an abundance of substructure which is approximately self-similar to that of the Galactic halo, then I show that additional boosts coming from the density enhancements of these small substructures and their small velocity dispersions enhance the dark matter annihilation cross section even further. I find that very large boost factors (10 5 to 10 9 ) are obtained in a large class of models. The implications of these boost factors for the detection of dark matter annihilation from dwarf Spheroidal galaxies in the Galactic halo are such that, generically, they outshine the background gamma-ray flux and are detectable by the Fermi Gamma-ray Space Telescope.

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Constraining the dark matter annihilation cross-section with Cherenkov telescope observations of dwarf galaxies

Cited by 39 publications

References 64 publications

VERITAS deep observations of the dwarf spheroidal galaxy Segue 1

VERITAS deep observations of the dwarf spheroidal galaxy Segue 1

Veritas Search for Vhe Gamma-Ray Emission From Dwarf Spheroidal Galaxies

Substructure boosts to dark matter annihilation from Sommerfeld enhancement

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