Relaxation in a Fuzzy Dark Matter Halo
Relaxation in a Fuzzy Dark Matter Halo
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模糊暗物质光环中的松弛
DOI：
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发表时间：
2018
影响因子：
4.9
通讯作者：
S. Tremaine
中科院分区：
文献类型：
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作者：
Ben Bar;Jean;S. Tremaine
暗物质可能是由轻玻色子组成的，在典型的星系势中具有布罗意波长。这种“模糊”暗物质（模糊暗物质（FDM））在比德布罗意布罗意波长大得多的尺度上表现得像冷暗物质（CDM），但可能解决CDM在小尺度上解释星系性质时面临的一些挑战（）。由于其波动性质，FDM在永不衰减的德布罗意布罗意尺度上表现出随机密度波动。这些波动产生的引力场散射了恒星和黑洞，导致它们的轨道在相空间中扩散。我们表明，这个弛豫过程可以使用与分析N体系统中经典两体弛豫相同的工具进行定量分析，并且可以通过将FDM波动视为准粒子来描述，其中星系中的有效质量具有恒定的圆速度。这种新的弛豫机制可能会使超大质量黑洞或球状星团的螺旋停止，因为在几百秒差距半径处的动力学摩擦，并且可以加热和扩大星系的中心区域。这些过程可以用来限制可能构成FDM的轻玻色子的质量。
Dark matter may be composed of light bosons, , with a de Broglie wavelength in typical galactic potentials. Such “fuzzy” dark matter (fuzzy dark matter (FDM)) behaves like cold dark matter (CDM) on much larger scales than the de Broglie wavelength, but may resolve some of the challenges faced by CDM in explaining the properties of galaxies on small scales ( ). Because of its wave nature, FDM exhibits stochastic density fluctuations on the scale of the de Broglie wavelength that never damp. The gravitational field from these fluctuations scatters stars and black holes, causing their orbits to diffuse through phase space. We show that this relaxation process can be analyzed quantitatively with the same tools used to analyze classical two-body relaxation in an N-body system, and can be described by treating the FDM fluctuations as quasiparticles, with effective mass in a galaxy with a constant circular speed of . This novel relaxation mechanism may stall the inspiral of supermassive black holes or globular clusters due to dynamical friction at radii of a few hundred parsecs and can heat and expand the central regions of galaxies. These processes can be used to constrain the mass of the light bosons that might comprise FDM.