Multiresolution Analysis of Substructure in Dark Matter Halos
نویسندگان
چکیده
Multiresolution analysis is applied to the problem of halo identification in cosmological N-body simulations. The procedure makes use of a discrete wavelet transform known as the à trous algorithm in combination with segmentation analysis. It has the ability to find halos in dense environments and to separate multiple levels of substructure, as is illustrated in the analysis of a 500,000 particle halo. Over 600 subhalos are identified and their physical properties are discussed. Subject headings: dark matter – galaxies: halos – methods: n-body simulations
منابع مشابه
Lensing Optical Depth for Substructure and Isolated Dark Matter Halos
Multiple-image quasar lenses can be used to constrain the substructure mass fraction in galaxy-sized dark matter halos via anomalous flux ratios of lensed images. The flux ratios, however, can be affected by both the substructure in the lens halo and by isolated small-mass halos along the entire line-ofsight to the lensed source. While lensing by dark matter clumps near the lens galaxy is more ...
متن کاملSubstructure in Cdm Halos and the Heating of Stellar Disks
Numerical simulations have revealed the presence of long-lived substructure in Cold Dark Matter (CDM) halos. These surviving cores of past merger and accretion events vastly outnumber the known satellites of the Milky Way. This finding has prompted suggestions that substructure in cold dark matter (CDM) halos may be incompatible with observation and in conflict with the presence of thin, dynami...
متن کاملDarkMatter Halos from the Inside Out
The balance of evidence indicates that individual galaxies and groups or clusters of galaxies are embedded in enormous distributions of cold, weakly interacting dark matter. These dark matter “halos” provide the scaffolding for all luminous structures in the universe, and their properties comprise an essential part of the current cosmological model. I review the internal properties of dark matt...
متن کاملOn the destruction and over - merging of darkhalos in dissipationless N - body
N-body simulations that follow only a collisionless dark matter component have failed to produce galaxy halos or substructure within dense environments. We investigate the `over-merging' problem analytically and with numerical simulations, by calculating dissolution timescales of halos due to physical and arti cial dynamical e ects. The numerical resolution that has recently been attained is su...
متن کاملMeasuring Dark Matter Substructure with Galaxy-Galaxy Flexion Statistics
It is of great interest to measure the properties of substructures in dark matter halos at galactic and cluster scales. Here we suggest a method to constrain substructure properties using the variance of weak gravitational flexion in a galaxy-galaxy lensing context. We show the effectiveness of flexion variance in measuring substructures in N-body simulations of dark matter halos, and present t...
متن کامل