Revealing fine structures of galactic dark matter halos and its implication for dark matter detection experiments

2014 Fiscal Year Final Research Report

• Project/Area Number: 24740115
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Astronomy
• Research Institution: University of Tsukuba
• Principal Investigator: ISHIYAMA Tomoaki 筑波大学, 計算科学研究センター, 研究員 (90616426)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: ダークマター / サブハロー / ダークマター検出 / 大規模シミュレーション / 銀河

Outline of Final Research Achievements

The smallest dark matter halos are formed first in the early universe. According to recent studies, the central density cusp is much steeper in these halos than in larger halos. We present results of very large cosmological N-body simulations of the hierarchical formation and evolution of halos over a wide mass range, beginning from the formation of the smallest halos. We confirmed early studies that the inner density cusps are steeper in halos at the free streaming scale. The cusp slope gradually becomes shallower as the halo mass increases. The slope of halos 50 times more massive than the smallest halo is approximately 1.3. The cusp slope of halos above the free streaming scale seems to be reduced primarily due to major merger processes. The concentration, estimated at the present universe, is predicted to be 60-70, consistent with theoretical models and earlier simulations, and ruling out simple power law mass-concentration relations.

Free Research Field

天文学