发表机构
University of Alabama Huntsville; European Southern Observatory; Gemini South, Gemini Observatory, NSF’s NOIRLab; The Pennsylvania State University; Center for Exoplanets and Habitable Worlds, The Pennsylvania State University; Michigan State University; Jet Propulsion Laboratory, California Institute of Technology; University of Geneva; The University of California, Irvine（亨茨维尔阿拉巴马大学; 欧洲南方天文台; 吉米南望远镜，吉米天文台，美国国家科学基金会NOIR实验室; 宾夕法尼亚州立大学; 系外行星与宜居世界中心，宾夕法尼亚州立大学; 密歇根州立大学; 喷气推进实验室，加州理工学院; 日内瓦大学; 加州大学尔湾分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文介绍首次银河系尺度极端精度径向速度巡天，利用VLT/ESPRESSO观测宁静次巨星，以约50厘米/秒精度测量银河系加速度，约束暗物质分布，为下一代极大望远镜巡天探路。
AI 中文摘要
我们描述了首次银河系尺度的极端精度径向速度（EPRV）巡天，并概述了我们的目标：测量银河系加速度并推导银河系内暗物质分布的约束。我们瞄准太阳半径一千秒差距（kpc）内、相对于银道面垂直高度约2千秒差距的宁静次巨星。本文描述的观测使用甚大望远镜（VLT）上的岩石系外行星与稳定光谱观测阶梯光栅光谱仪（ESPRESSO），于2021年至2025年间进行。我们最初以约70厘米/秒的典型径向速度精度运行，以从恒星活动指标中筛选宁静恒星，目前正以约50厘米/秒的精度运行。我们选择了低恒星抖动（由其径向速度随历元的散布确定）的恒星，目标是使它们在大约十年时间尺度上提供银河系加速度的测量。我们称此为“黄金”样本。我们还识别了可能具有伴星（无论是褐矮星还是行星伴星）或迄今未知的恒星双星的恒星，这些已从巡天中剔除。对于少数情况，我们给出了伴星质量和轨道周期的初步约束。我们还展示了“黄金”次巨星样本的光球层和基本恒星参数。这项首次银河系尺度EPRV巡天为下一代极大望远镜巡天提供了探路者，开启了直接绘制银河系乃至更远区域引力加速度场的可能性。
英文摘要
We describe the first Galactic-scale extreme-precision radial velocity (EPRV) survey and outline our goals of measuring Galactic accelerations and deriving constraints on the dark matter distribution in our Galaxy. We are targeting quiet subgiant stars within a kiloparsec in radius of the Sun and about 2 kiloparsec in vertical height relative to the Galactic mid-plane. The observations described here were carried out using the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) at the Very Large Telescope (VLT), between 2021-2025. We began by operating at a typical RV precision of $\sim$ 70 cm/s to select quiet stars from stellar activity indicators, and are now operating at $\sim$ 50 cm/s. We selected stars with low stellar jitter (determined from their RV scatter as a function of epoch) with the goal that they yield a measurement of the Galactic acceleration on approximately a decade timescale. We refer to this as our ``gold" sample. We also identify stars with possible companions (either brown dwarfs or planetary companions) or hitherto unknown stellar binaries that we have culled from our survey. For a few cases, we present initial constraints on the companion mass and orbital period. We also present the photospheric and fundamental stellar parameters for our ``gold" sample of sub-giant stars. This first Galactic-scale EPRV survey provides a pathfinder for next-generation surveys with extremely large telescopes, opening the possibility of directly mapping the gravitational acceleration field across the Milky Way and potentially beyond.
Comments33 pages; 24 figures
