《Gaia》天体测量亚恒星伴星的视向速度后续观测：六个确认的褐矮星与十三个伪装双星
Radial velocity follow-up of \textit{Gaia} astrometric substellar companions: six confirmed brown dwarfs and 13 impostor binaries
- Aarhus Universitet（奥胡斯大学）
- Princeton University（普林斯顿大学）
- Schmidt Sciences（施密特科学）
- Universiteit van Amsterdam（阿姆斯特丹大学）
- Nordic Optical Telescope（北欧光学望远镜）
- The Pennsylvania State University（宾夕法尼亚州立大学）
- Johns Hopkins University（约翰斯·霍普金斯大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过视向速度后续观测验证20个Gaia天体测量亚恒星伴星候选体，确认6个褐矮星并识别13个伪装双星，证明轨道解在不确定度内可靠。
AI中文摘要：
凭借微角秒级精度，《Gaia》使得亚恒星伴星的天体测量发现成为可能。然而，需要进行后续观测以检验轨道解并排除天体物理假阳性。我们验证并表征了20个《Gaia》数据发布3（DR3）亚恒星伴星天体测量候选体，其双重目标是识别假阳性并为真实伴星推导稳健的物理参数。我们分别使用北欧光学望远镜上的FIES、ESO 3.6米望远镜上的NIRPS以及WIYN望远镜上的NEID进行了高分辨率光谱观测。双线光谱双星被识别为假阳性，幸存系统通过《Gaia》天体测量与视向速度联合建模进行表征。其中十三个候选体被证明是近孪生双星，其光心天体测量运动小到足以模拟单星对亚恒星伴星的响应。我们确认六个伴星为褐矮星，质量范围在约26至68倍木星质量之间，其中两个为首次确认。与早期对较低质量《Gaia》候选体的研究相比，我们发现天体测量轨道解通常在所述不确定度内是可靠的。
英文摘要：
With microarcsecond precision, \textit{Gaia} has made the astrometric discovery of substellar companions feasible. However, follow-up observations are needed to check on orbital solutions and rule out astrophysical false positives. We validate and characterise a sample of 20 \textit{Gaia} Data Release 3 (DR3) astrometric candidates for substellar companions, with the dual goal of identifying false positives and deriving robust physical parameters for genuine companions. We performed high-resolution spectroscopy using FIES, NIRPS, and NEID at the Nordic Optical Telescope, the ESO 3.6m telescope, and the WIYN Telescope, respectively. Double-lined spectroscopic binaries were identified as false positives, and surviving systems were characterised through joint \textit{Gaia} astrometry and radial velocity modelling. Thirteen of the candidates proved to be near-twin binary stars for which the astrometric motion of the center of light is small enough to mimic that of a single star in response to a substellar companion. We confirm that six companions are brown dwarfs with masses in the range ${\sim}26$--$68\,M_\mathrm{Jup}$, two of them for the first time. In contrast to earlier studies of lower-mass \textit{Gaia} candidates, we find that the astrometric orbital solutions are generally reliable to within the stated uncertainties.
