Tidal Destruction of The First Dark Microhalos

Abstract

We point out that the usual self-similarity in cold dark matter models is broken by encounters with individual normal galactic stars on sub-pc scale. Tidal heating and stripping must have redefined the density and velocity structures of the population of the Earth-mass dark matter halos, which are likely to have been the first bound structures to form in the Universe. The disruption rate depends strongly on {\it galaxy types} and the orbital distribution of the microhalos; in the Milky Way, stochastic radial orbits are destroyed first by stars in the triaxial bulge, microhalos on non-planar retrograde orbits with large pericenters and/or apocenters survive the longest. The final microhalo distribution in the {\it solar neighborhood} is better described as a superposition of filamentry microstreams rather than as a set of discrete spherical clumps in an otherwise homogeneous medium. We discuss its important consequences to our detections of microhalos by direct recoil signal and indirect annihilation signal.

13 pages, 3 figures, Astrophysical Journal, accepted

References in corpus (10)

• Earth-mass dark-matter haloes as the first structures in the early Universe
• The first WIMPy halos
• Directional statistics for WIMP direct detection
• Searching for Dark Matter with Future Cosmic Positron Experiments
• Destruction of small-scale dark matter clumps in the hierarchical structures and galaxies
• Kaluza-Klein Dark Matter and the Positron Excess
• Mini-dark halos with intermediate mass black holes
• The Role of Antimatter Searches in the Hunt for Supersymmetric Dark Matter
• Difficulty of detecting minihalos via $\gamma$-rays from dark matter annihilation
• Indirect Detection of Dirac Right-Handed Neutrino Dark Matter

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