Clustering in the Phase Space of Dark Matter Haloes. II. Stable Clustering and Dark Matter Annihilation

Abstract

We present a model for the structure of the particle phase space average density ($P^{2}SAD$) in galactic haloes, introduced recently as a novel measure of the clustering of dark matter. Our model is based on the stable clustering hypothesis in phase space, the spherical collapse model, and tidal disruption of substructures, which is calibrated against the Aquarius simulations. Using this model, we can predict the behaviour of $P^{2}SAD$ in the numerically unresolved regime, down to the decoupling mass limit of generic WIMP models. This prediction can be used to estimate signals sensitive to the small scale structure of dark matter. For example, the dark matter annihilation rate can be estimated for arbitrary velocity-dependent cross sections in a convenient way using a limit of $P^{2}SAD$ to zero separation in physical space. We illustrate our method by computing the global and local subhalo annihilation boost to that of the smooth dark matter distribution in a Milky-Way-size halo. Two cases are considered, one where the cross section is velocity independent and one that approximates Sommerfeld-enhanced models. We find that the global boost is $\sim 10-30$, which is at the low end of current estimates (weakening expectations of large extragalactic signals), while the boost at the solar radius is below the percent level. We make our code to compute $P^{2}SAD$ publicly available, which can be used to estimate various observables that probe the nanostructure of dark matter haloes.

12 pages, 7 figures, version published in MNRAS (minor corrections), publicly available code in IDL at http://spaces.perimeterinstitute.ca/p2sad/

References in corpus (10)

• Observation of an anomalous positron abundance in the cosmic radiation
• A Theory of Dark Matter
• Dark Matter Results from 225 Live Days of XENON100 Data
• Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
• A blueprint for detecting supersymmetric dark matter in the Galactic halo
• Phase-space structure in the local dark matter distribution and its signature in direct detection experiments
• The Dark Matter Annihilation Signal from Galactic Substructure: Predictions for GLAST
• Dark matter interpretation of recent electron and positron data
• Galactic Substructure and Dark Matter Annihilation in the Milky Way Halo
• The cosmic X-ray and gamma-ray background from dark matter annihilation

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• Galactic PeV neutrinos from dark matter annihilation
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