To determine the local dark matter density (LDMD) of the solar system is a classical problem in astronomy. Recently, a novel method of determining the LDMD from stellar distribution and vertical velocity dispersion profiles perpendicular to the Galactic plane was devised. This method has the advantage of abolishing conventional approximations and using only a few assumptions. Our aims are to carefully scrutinize this method and to examine influences by uncertainties of astrometric observations. We discuss how the determinations of the LDMD vary with observational precisions on parallax, proper motion, and line-of-sight velocity measurements. To examine the influences by the observational imprecision, we created mock observation data for stars that are dynamical tracers based on an analytical galaxy model and applied parametrized observational errors to the mock data. We evaluated the accuracy of determining the LDMD by applying the method to the mock data. In addition, we estimated a sample size and observational precision required to determine the LDMD with accuracy. We find that the method is capable of determining the LDMD with accuracy if the sample size and observational precisions are satisfactory. The random errors of parallaxes and proper motions can cause systematic overestimation of the LDMD. We estimate the required precisions of the parallax measurements to be approximately 0.1-0.3 milliarcseconds at 1 kpc away from the Sun; the proper motion precisions do not seem to be as important as the parallaxes. From these results, we expect that using the Hipparcos catalog would overestimate the LDMD because of the imprecise parallax measurements if this method is applied; however, we emphasize the capability of the method. We expect that Gaia will provide data precise enough to determine the LDMD.
Zentrum für Astronomie der Universität Heidelberg, Astronomisches Rechen-Institut（海德堡大学天文中心，天文计算研究所）；Sydney Institute for Astronomy (SIfA), The University of Sydney（悉尼大学天体物理研究所）；Donald Bren School of Information and Computer Sciences, University of California, Irvine（加州大学欧文分校唐纳德布伦信息与计算机科学学院）；Astronomical Observatory, University of Warsaw（华沙大学天文台）；Astrophysics Division, National Centre for Nuclear Research（国家核研究中心天体物理学部）
Dents in the Mirror: A Novel Probe of Dark Matter Substructure in Galaxy Clusters from the Astrometric Asymmetry of Lensed Arcs
School of Physics and Astronomy, University of Minnesota（明尼苏达大学物理与天文学院）；Department of Astronomy and Astrophysics, University of Chicago（芝加哥大学天体物理学系）；Department of Physics and Astronomy, University of California, Los Angeles（加州大学洛杉矶分校物理与天文系）；Department of Physics, University of California at Santa Barbara（加州大学圣塔芭芭拉分校物理系）
On the Viability of Determining Galaxy Properties from Observations I: Star Formation Rates and Kinematics
通过对NewHorizon宇宙学流体动力学模拟中的一对合并的$z\sim2$星系进行后处理，利用LCARS（Light from Cloudy Added to RAMSES）将模拟星系的物理性质编码为H $α$发射线，探讨观测结果与发射星系物理性质的关系.通过对这些数据立方体进行模拟观测和分析，我们确定了银河系的哪些物理特性可以用欧洲极大望远镜（ELT）上的HARMONI摄谱仪恢复。我们能够估计星系的恒星形成率和动力学质量的合理程度的准确性，在一个因素的$1.81$和$1.38$的真实值。星系的运动学结构也恢复在模拟观测。此外，我们能够恢复径向配置文件的速度色散，因此能够计算如何动态比变化的函数，从星系中心的距离。最后，我们表明，当计算星系尺度的动力学比并不总是提供一个可靠的措施，星系的稳定性对重力或作为一个指标的一个小合并。
Detection of single-degenerate massive binaries with Gaia: The impact of blue supergiants, triples, mass precision, and high-precision parallax requirements
