FORMATION AND EVOLUTION OF SELF-INTERACTING DARK MATTER HALOS
FORMATION AND EVOLUTION OF SELF-INTERACTING DARK MATTER HALOS
复制标题
自相互作用暗物质晕的形成和演化
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
P. Shapiro
中科院分区：
文献类型：
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作者：
K. Ahn;P. Shapiro
我们已经推导出了第一个完全宇宙学的相似解，在非引力碰撞（即弹性散射）的存在下，冷暗物质（CDM）晕形成，这提供了一个分析理论的自相互作用暗物质（SIDM）假设晕密度分布的影响。碰撞向内输送热量，这是CDM密度分布的中心尖点，产生一个恒定密度的核心，而连续的注入将能量注入晕，以稳定核心，防止重力热灾难。这与先前基于孤立晕的分析相反，后者预测核心在哈勃时间内崩溃。这些解决方案改进了早期尝试模拟SIDM晕的形成和演化，提供比现有N体实验更深入的见解，并产生更精确的确定晕密度分布对CDM自相互作用截面值的依赖。对于不同的无量纲碰撞性参数Q <$σρbrvir rvir/λmfp（其中σ是单位质量的散射截面，ρB是宇宙平均物质密度，rvir是晕维里半径，λmfp是碰撞平均自由程），有不同的解.矮星系和低表面亮度（LSB）星系旋转曲线所偏好的具有恒定密度核心的密度分布最适合于最大平坦（Q = Qth）解。如果我们假设矮星和LSB星系形成于
We have derived the first, fully cosmological, similarity solutions for cold dark matter (CDM) halo formation in the presence of non-gravitational collisionality (i.e. elastic scattering), which provides an analytical theory of the effect of the self-interacting dark matter (SIDM) hypothesis on halo density profiles. Collisions transport heat inward, which flattens the central cusp of the CDM density profile to produce a constant-density core, while continuous infall pumps energy into the halo to stabilize the core against gravothermal catastrophe. This is contrary to previous analyses based upon isolated haloes, which predict core collapse within a Hubble time. These solutions improve upon earlier attempts to model the formation and evolution of SIDM haloes, offer deeper insight than existing N-body experiments, and yield a more precise determination of the dependence of halo density profile on the value of the CDM self-interaction cross-section. Different solutions arise for different values of the dimensionless collisionality parameter Q ≡ σρbrvir ∝ rvir/λmfp, where σ is the scattering cross-section per unit mass, ρb is the cosmic mean matter density, rvir is halo virial radius and λmfp is the collision mean free path. The maximum flattening of central density occurs for an intermediate value of Q, Qth ,a twhich the halo is maximally relaxed to isothermality. The density profiles with constant-density cores preferred by dwarf and low surface brightness (LSB) galaxy rotation curves are best fit by the maximally flattened (Q = Q th) solution. If we assume that dwarfs and LSB galaxies formed