AI 中文总结
本研究提出利用膨胀年轻恒星星协约束银河系引力势的新方法，结合Gaia DR4数据等可实现晕质量等参数的高精度约束，未来观测将提供互补工具。
AI 中文摘要
银河系的引力势对于理解我们银河系的演化以及暗物质的本质至关重要。我们提出一种利用膨胀的年轻恒星星协来约束银河系引力势的新方法。我们利用这些恒星具有共同致密起源的物理约束，重构它们最可能的轨道，并推断其演化所处的引力势。我们用位置协方差矩阵的迹和行列式定义星协的大小。通过在不同试验引力势中反向积分合成星协，我们证明了如何通过最小化这些指标来识别真实的引力势。我们表明，尽管当前观测误差仍然过大，但未来的观测将使我们能够区分不同的引力势。我们的结果显示，利用盖亚（Gaia）DR4天体测量数据和低于0.2 km/s的视向速度误差，单个星协可将暗物质晕质量约束精度达到0.6万亿太阳质量，浓度参数约束精度小于0.8，不过存在显著的简并性。此外，我们还表明，推断出的动力学回溯年龄对引力势敏感，这表明独立的年龄信息有助于打破现有简并性，但回溯年龄估计也与所假设的引力势相关。膨胀的恒星星协携带着其演化所处引力势的信息，随着下一代天体测量和高精度视向速度观测的到来，它们将成为约束银河系引力势的补充工具。
英文摘要
The gravitational potential of the Milky Way is fundamental for understanding the evolution of our Galaxy and the nature of dark matter. We introduce a new method to constrain the Galactic potential using expanding young stellar associations. We exploit the physical constraint that these stars share a common, compact origin to reconstruct their most likely orbits and infer the gravitational potential in which they have evolved. We define the size of an association using the trace and determinant of its position covariance matrix. By integrating synthetic associations backward in different trial potentials, we show how the true potential can be identified as the one that minimises these metrics. We demonstrate that, while current observational errors are still too large, upcoming observations will allow us to distinguish between different potentials. Our results suggest that with Gaia DR4 astrometry and radial velocity errors below 0.2 km/s, the halo mass can be constrained with a precision of 0.6 trillion solar masses and the concentration with a precision of < 0.8 using a single association, albeit with significant degeneracies. In addition, we show that the inferred dynamical traceback age is sensitive to the gravitational potential, suggesting that independent age information can help break existing degeneracies, but also that traceback-age estimates are not independent of the assumed potential. Expanding stellar associations carry information about the gravitational potential in which they have evolved. With the arrival of next-generation astrometry and high-precision radial velocities, they will provide a complementary tool for constraining the Galactic potential.
Comments13 pages, 8 figures. Accepted in A&A. Full analysis code is provided
