Some astrophysical consequences of the existence of a heavy stable neutral lepton

Gunn, J. E.; Lee, B. W.; Lerche, I.; Schramm, David N.; Steigman, Gary

doi:10.1086/156335

Cited by 326 publications

(210 citation statements)

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“…which are called J factor and D factor (e.g., Gunn et al 1978;Bergström et al 1998;Geringer-Sameth et al 2015b). These factors correspond to the line-of-sight integrated dark matter density squared for annihilation and the dark matter density for decay, respectively, within solid angle ∆Ω.…”

Section: Astronomical Factor For Annihilation and Decaymentioning

confidence: 99%

“…Indirect searches for dark matter annihilations or decays are one of the unique ways of constraining numerous particle candidates for dark matter (e.g., Gunn et al 1978;Bergström 2012, for review). In particular, the indirect detections utilizing γ-ray or X-rays emissions are suitable for limiting the heavier dark matter Contact e-mail: kohei.hayashi@ipmu.jp candidates of ∼ 0.1 -1 TeV, such as weakly interacting massive particles (WIMPs).…”

Section: Introductionmentioning

confidence: 99%

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Dark matter annihilation and decay from non-spherical dark halos in galactic dwarf satellites

Hayashi

Ichikawa

Matsumoto

et al. 2016

Mon. Not. R. Astron. Soc.

111

119

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The dwarf spheroidal galaxies (dSphs) in the Milky Way are the primary targets in the indirect searches for particle dark matter. To set robust constraints on candidate of dark matter particles, understanding the dark halo structure of these systems is of substantial importance. In this paper, we first evaluate the astrophysical factors for dark matter annihilation and decay for 24 dSphs, with taking into account a non-spherical dark halo, using generalized axisymmetric mass models based on axisymmetric Jeans equations. First, from a fitting analysis of the most recent kinematic data available, our axisymmetric mass models are a much better fit than previous spherical ones, thus, our work should be the most realistic and reliable estimator for astrophysical factors. Secondly, we find that among analysed dSphs, the ultra-faint dwarf galaxies Triangulum II and Ursa Major II are the most promising but large uncertain targets for dark matter annihilation while the classical dSph Draco is the most robust and detectable target for dark matter decay. It is also found that the non-sphericity of luminous and dark components influences the estimate of astrophysical factors, even though these factors largely depend on the sample size, the prior range of parameters and the spatial extent of the dark halo. Moreover, owing to these effects, the constraints on the dark matter annihilation cross-section are more conservative than those of previous spherical works. These results are important for optimizing and designing dark matter searches in current and future multi-messenger observations by space and ground-based telescopes.

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Section: Astronomical Factor For Annihilation and Decaymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dark matter annihilation and decay from non-spherical dark halos in galactic dwarf satellites

Hayashi

Ichikawa

Matsumoto

et al. 2016

Mon. Not. R. Astron. Soc.

111

119

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“…First, the condition σ 2 ≤ |c 2 s | is not very restrictive, since the CDM cools rapidly with the Universe's expansion, with temperature scaling as (1 + z) 2 once the particles become non-relativistic. For example, for CDM particles of mass ∼ GeV with weak scale cross sections, the CDM temperature is ∼ 10 −4 K at decoupling [35]. However, after perturbations go nonlinear and violent relaxation takes place in CDM halos, the effective coarse-grained velocity dispersion becomes much larger.…”

Section: Domain Of Validity Of Fluid Description Of Dark Mattermentioning

confidence: 99%

Adiabatic instability in coupled dark energy/dark matter models

2008

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We consider theories in which there exists a nontrivial coupling between the dark matter sector and the sector responsible for the acceleration of the universe. Such theories can possess an adiabatic regime in which the quintessence field always sits at the minimum of its effective potential, which is set by the local dark matter density. We show that if the coupling strength is much larger than gravitational, then the adiabatic regime is always subject to an instability. The instability, which can also be thought of as a type of Jeans instability, is characterized by a negative sound speed squared of an effective coupled dark matter/dark energy fluid, and results in the exponential growth of small scale modes. We discuss the role of the instability in specific coupled CDM and Mass Varying Neutrino (MaVaN) models of dark energy, and clarify for these theories the regimes in which the instability can be evaded due to non-adiabaticity or weak coupling.

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“…While the MACHOs searches [2] indicate that an astrophysical solution is rather unlikely, most efforts are now concentrated on searches for Weakly Interacting Massive Particles (WIMPs) [3]. These particles would belong to the Cold Dark Matter scenario (CDM); they would annihilate and suffer from negligible damping effects at a cosmological scale.…”

Section: Introductionmentioning

confidence: 99%