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Tidal Disruption of the First Dark Microhalos

Zhao, HongSheng and Hooper, Dan and Angus, Garry W. and Taylor, James E. and Silk, Joseph (2007) Tidal Disruption of the First Dark Microhalos. Astrophysical Journal, 654 (2). pp. 697-701. ISSN 0004-637X.

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We point out that the usual self-similarity in cold dark matter models is broken by encounters with individual normal galactic stars on a subparsec 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 galaxy types and the orbital distribution of the microhalos; in the MilkyWay, stochastic radial orbits are destroyed first by stars in the triaxial bulge, and microhalos on nonplanar retrograde orbits with large pericenters and/or apocenters survive the longest. The final microhalo distribution in the solar neighborhood is better described as a superposition of filamentary microstreams rather than as a set of discrete spherical clumps in an otherwise homogeneous medium. This has important consequences to our detections of microhalos by direct recoil signal and indirect annihilation signal.

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Additional Information:© 2007. The American Astronomical Society. H. Z. acknowledges support from PPARC Advanced Fellowship andOutstanding OverseaYoung Scholarship fromthe Chinese Academy of Science. G. W. A. acknowledges an overseas fieldwork grant from PPARC and hospitality from Beijing University. J. E. T. acknowledges financial support from the NSF (grant AST 03-07859) and the DoE (contract DE-FG02-04ER41316).
Funding AgencyGrant Number
Particle Physics and Astronomy Research CouncilUNSPECIFIED
Chinese Academy of ScienceUNSPECIFIED
NSFAST 03-07869
Subject Keywords:dark matter
Issue or Number:2
Record Number:CaltechAUTHORS:20091009-163405701
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16237
Deposited By: Kristin Buxton
Deposited On:09 Oct 2009 23:41
Last Modified:03 Oct 2019 01:09

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