发表机构
Massachusetts Institute of Technology; Case Western Reserve University; Princeton University; Technical University of Denmark; University of Copenhagen（麻省理工学院; 凯斯西储大学; 普林斯顿大学; 丹麦技术大学; 哥本哈根大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出一种基于投影星流曲率方向的几何诊断方法，利用星流凸段比率统计约束星系晕形状，从而区分冷暗物质与自相互作用暗物质，预测巡天数据可达5σ显著性。
AI 中文摘要
暗物质的本质决定了星系晕的形状：无碰撞冷暗物质（CDM）预言三轴椭球晕，而自相互作用暗物质（SIDM）中的散射则使其趋向球形。我们表明，一个大型的投影星流轨道目录可以在不对任何单条星流或引力势进行详细建模的情况下，统计性地约束晕的形状，从而约束暗物质的粒子本质。我们为星流开发了一种新的几何诊断方法：如果星流上任意一段的曲率指向偏离宿主星系投影质心，则该星流证伪了包括球形势在内的广泛势类别。我们将这样的段称为凸段。该诊断仅需要投影星流轨道和宿主中心估计，不需要运动学、距离、前身星模型或对单个宿主势的拟合。晕的三轴性决定了星流呈现凸段的比率，使得该比率成为晕形状分布和底层暗物质模型的可观测特征。我们预测，即将到来的巡天级星流形态目录可以在高达$5\sigma$的置信水平上区分CDM和SIDM。
英文摘要
The nature of dark matter sets the shape of galactic halos: collisionless cold dark matter (CDM) predicts triaxial halos, while scattering in self-interacting dark matter (SIDM) rounds them toward sphericity. We show that a large catalog of projected stellar stream tracks can statistically constrain halo shapes, and therefore the particle nature of dark matter, without detailed modeling of any individual stream or gravitational potential. We develop a new geometric diagnostic for stellar streams: if the curvature of any segment along a stream points away from the host galaxy's projected center of mass, then that stream falsifies broad classes of potentials, including spherical ones. We call such a segment convex. The diagnostic needs only a projected stream track and a host-center estimate, requiring no kinematics, distances, progenitor model, or fit to individual host potentials. Halo triaxiality sets the rate at which streams show convex segments, making this rate an observable of the halo-shape distribution and the underlying dark-matter model. We forecast that upcoming survey-scale stream morphology catalogs can discriminate between CDM and SIDM at up to $5σ$.
Comments19 pages (+3 appendix), 7 figures (+1 appendix)
