标题： NGC 5963的暗晕作为低速状态下暗物质自相互作用的限制条件 显示英文标题

标题： The Dark Halo of NGC 5963 as a Constraint on Dark Matter Self-Interaction at the Low Velocity Regime

摘要： 自相互作用暗物质被提出作为一种假设，以解释星系中暗物质晕的密度分布浅中央斜率。 为了与星系团尺度上的观测研究一致，截面应该与碰撞速度成反比关系。 本文考虑了低表面亮度（LSB）星系NGC 5963的晕的密度分布剖面，以限制碰撞速度为$\sim 150$km/s$^{-1}$（即低速区域）时暗物质截面的上限。 经过与宇宙学模拟校准后，我们发现NGC 5963中推断出的大暗物质浓度和中心暗物质密度与单位质量的有效碰撞截面大于0.2 cm^2/g不一致。 为了弥补由冷却重子引起的绝热收缩导致的核心减少，进行了修正。 我们的限制涉及许多简化但始终保守的假设，排除了依赖于速度的截面最后允许的区间来解释LSB星系中的平坦密度核。 还讨论了暗物质性质的影响。 显示英文摘要

摘要： Self-interacting dark matter has been proposed as a hypothesis to explain the shallow central slopes of the density profiles of dark matter halos in galaxies. In order to be consistent with observational studies at scales of galaxy clusters, the cross section should scale inversely with the velocity of collision. In this paper we consider the mass density profile of the halo of the low surface brightness (LSB) galaxy NGC 5963 to place an upper limit on the dark matter cross section for collisions with velocities $\sim 150$ km s$^{-1}$, i.e. at the low velocity regime. After calibrating against cosmological simulations, we found that the large inferred dark matter concentration and central dark matter density in NGC 5963 are inconsistent with an effective collisional cross section per unit of mass >0.2 cm^2/g. Corrections were applied in order to account for reduction of the core by the adiabatic contraction caused by cooling baryons. Our limits that involve a number of simplifying, but always conservative, assumptions, exclude the last permitted interval for velocity-dependent cross sections to explain the flat density core in LSB galaxies. Implications for the nature of dark matter are also discussed.