发表机构
Università degli Studi di Bologna; INAF; Pontificia Universidad Católica de Chile; Max Planck Institute for Astronomy; Universität Heidelberg; Johns Hopkins University（博洛尼亚大学; 意大利国家天体物理研究所; 智利天主教 Pontificia 大学; 马克斯·普朗克天文学研究所; 海德堡大学; 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 中文总结
本研究通过动力学分析评估四颗关联到核恒星盘的经典造父变星的成员身份，发现仅GCC-a可能属于该结构，GCC-b和GCC-c无动力学关联，这对核恒星盘约2000万年前的恒星形成爆发假说提出质疑。
AI 中文摘要
（节选）已有四颗经典造父变星被关联到核恒星盘（NSD），这表明2000万年前曾发生过一次恒星形成爆发。本研究分析这四颗造父变星的所有可用数据，以确定它们是核恒星盘的真实成员还是该区域的闯入者，从而证实或排除文献中提出的恒星形成爆发假说。我们的动力学分析基于包含银河系内所有成分的更新版MWpotential，同时对观测误差和模型依赖性进行了全面的系统误差研究。结果显示，仅一颗造父变星可能属于核恒星盘，另外两颗的轨道则远超出该结构；考虑观测不确定性后，后两颗造父变星的误差分布生成的模拟样本中，仅有23%至28%与核恒星盘兼容。第四颗造父变星没有自行测量数据，且光变曲线分析对其作为经典造父变星的分类提出质疑。通过对归属于核恒星盘的造父变星可用数据进行全面动力学分析，我们评估了它们对该结构的成员身份。在以空前深度分析的三颗造父变星中，GCC-a可能是核恒星盘成员，而GCC-b和GCC-c在动力学上似乎与该结构无关联；考虑观测不确定性后，GCC-b和GCC-c的模拟样本中仍有不可忽视的比例与核恒星盘兼容，因此基于当前数据无法完全排除它们的成员身份。仅一颗造父变星的可靠关联，使人们对核恒星盘约2000万年前发生过一次恒星形成事件的观点产生怀疑。
英文摘要
(abridged) Four classical Cepheids have been associated to the Nuclear Stellar Disk (NSD), suggesting a burst of star formation 20 Myrs ago. In this work, we analyse all available data for these four Cepheids in order to gauge if they are bona fide members of the NSD or interlopers in the region. This allows to confirm or rule out the star formation burst hypothesised in the literature. Our dynamical analysis is based on an updated MWpotential that includes all components of the inner Galaxy. We conduct a thorough study of possible systematics, taking into account both observational errors and model dependencies. Our results suggest that only one Cepheid likely belongs to the NSD, while the orbits of other two extend well beyond it. Accounting for observational uncertainties, only 23-28 percent of the realisations sourced from the error distributions for the latter two are compatible with the NSD. For the fourth there are no proper motion measurements available and the light curve analysis puts into question its classification as a classical Cepheid. Through a comprehensive dynamical analysis of available data on the Cepheids attributed to the NSD, we gauged their membership to this structure. Out of the three Cepheids analysed in unprecedented depth, GCC-a is likely a member of the NSD while both GCC-b and GCC-c do not seem dynamically linked to it. Factoring in the observational uncertainties, a non-negligible percentage of the realisations for GCC-b and GCC-c are still compatible with the NSD, thus membership cannot be completely excluded for either with current data. The robust association of only one Cepheid casts doubt on the occurrence of a star formation episode in the NSD, about 20 Myrs ago.
CommentsAccepted for publication in A&A. 10 pages and 14 figures in the main text, 4 pages and 8 figures in the appendix
