银河系星流中可探测的子晕撞击
Detectable subhalo impacts in Milky Way streams
AI总结：
该研究开发了流程与统计框架，基于LSST等数据预测银河系星流的可探测子晕撞击数，发现Jet等5条星流预期撞击数超0.2，不同暗物质模型会显著影响撞击数量。
AI中文摘要：
暗物质子晕会在银河系的恒星星流中留下引力印记。观测子晕的单个强撞击为限制和发现低至10^6 M⊙的潜在暗子晕提供了极具吸引力的方法，可用于对暗物质的粒子物理性质开展新的检验。我们开发了一套流程和统计框架，基于LSST和Via等巡天的形态学与运动学数据，预测恒星星流上可探测子晕撞击的预期数量。从已确认的恒星星流目录出发，我们重点关注14条有前景的星流，这些星流可通过粒子喷流算法进行相对良好的建模。我们对可探测撞击的判定标准为：星流与最佳拟合多项式代理模型的偏差达到95%置信水平（CL），该标准考虑了星流建模的不确定性，并抑制了与这些不确定性简并的远距离撞击的影响。在所研究的14条星流中，我们发现5条星流的可探测撞击预期数量大于0.2。利用LSST和Via的数据，Jet星流的可探测撞击预期数量为5.15^+1.10_-0.95，其次是Orphan-Chenab（1.40^+0.62_-0.47）、ATLAS-Aliqa Uma（1.25^+0.60_-0.44）、GD-1（0.55^+0.43_-0.28）和Palomar 5（0.40^+0.39_-0.23），误差棒为泊松均值的95%置信区间。这些数值依赖于所假设的子晕分布，可能导致预测存在数倍的系统不确定性。我们还考虑了不同粒子暗物质模型对撞击数量的影响，发现处于当前质量界限的热暗物质和模糊暗物质模型会使撞击数量被抑制约4倍，而自相互作用暗物质的玩具模型则会使撞击数量提升O(1)量级。
英文摘要：
Dark matter subhalos leave gravitational imprints in the stellar streams of the Milky Way. Observing individual strong impacts of subhalos offers a compelling way to constrain and discover potentially dark subhalos down to $10^6 M_\odot$, allowing for new tests of the particle physics properties of dark matter. We develop a pipeline and statistical framework to forecast the expected number of detectable subhalo impacts on stellar streams, based on morphological and kinematic data from surveys such as LSST and Via. Starting from a catalog of confirmed stellar streams, we focus our efforts on 14 promising streams that are relatively well-modeled with a particle spray algorithm. Our criteria for a detectable impact is a deviation at 95% CL from the best-fit polynomial proxy model for the stream, which accounts for stream modeling uncertainties and regulates the effect of distant impacts that are degenerate with these uncertainties. Among the 14 streams studied, we find that 5 streams have an expected number of detectable impacts greater than 0.2. With LSST and Via data, the stream Jet has $5.15^{+1.10}_{-0.95}$ expected detectable impacts, followed by Orphan-Chenab ($1.40^{+0.62}_{-0.47}$), ATLAS-Aliqa Uma ($1.25^{+0.60}_{-0.44}$), GD-1 ($0.55^{+0.43}_{-0.28}$), and Palomar 5 ($0.40^{+0.39}_{-0.23}$), where error bars are the 95% containment on the Poisson mean. These values rely on the assumed subhalo population, which can give a factor of few systematic uncertainty in the predictions. We also consider effects of different particle dark matter models on the number of impacts, finding a suppression by a factor of $\sim 4$ for warm dark matter and fuzzy dark matter models at their current mass bounds and an $O(1)$ enhancement for a toy model of self-interacting dark matter.
