利用LAMOST光谱对银河系三维结构和致密天体质量分布进行深入研究

The advent of the Large Sky Area Multiple Object fiber Spectroscopic Telescope (LAMOST) provides a unique opportunity for studying the compact objects in the Milky Way. Based on the results of LAMOST Pilot Survey and its real performance, we have devised an original method to select black hole binary candidates in the low X-ray states that would have been missed by the conventional X-ray outburst dependent method, using LAMOST spectra of to UV-excess sources to discard contaminants that are not black hole binaries. We plan to measure the primary mass via dynamical means with follow-up observations using telescopes both in China and abroad, and, with black holes accumulating, verify whether there really is a scarcity of low-mass stellar black holes in the Milky Way. Our LAMOST survey of UV-excess sources will also collect about ten thousand massive and hot white dwarfs, doubling currently known white dwarfs, and testing whether white dwarfs can become Type Ia supernovae through accreting and accumulating matter from a secondary, and quantifying the SNe Ia rate through this channel. We will also devise a new stellar spectral classification scheme based on spectral lines instead of spectral templates, which can tell binaries from single stars easily, thus solving the binary contanimation problem in the studies of 3D Milky Way structure and Galactic dynamics. Combining LAMOST data, follow-up observations, theoretical modelling, we expect to deepen our understanding in compact objects, binary formation and evolution, 3D Milky Way structure and Galactic dynamics.

我国重大科研装置“大天区面积多目标光纤光谱巡天望远镜”（LAMOST）为银河系致密天体的研究提供了前所未有的机遇。本项目立足于LAMOST先导巡天结果和现有技术指标，创新性地利用紫外盈余源的光学光谱来筛选黑洞候选体，以发现大量被传统方法遗漏的处于X射线低态的黑洞双星，利用国内外望远镜开展后续监测测量动力学质量，以期解决小质量恒星级黑洞是否存在这一重大问题。本项目将在大样本的基础上检验是否存在质量接近钱德拉塞卡极限的白矮星，评估白矮星通过双星吸积形成Ia型超新星的几率。本项目将发展基于谱线族的恒星光谱分类方法，由光谱本身来甄别寻常恒星与双星，从而有效解决银河系三维结构和动力学研究中的双星污染问题，得到分辨率更高更可信的结果。本项目将采取观测、数据分析和理论研究相结合的研究方法，把理论分析紧密地建立在观测结果的基础上，以取得对致密天体双星的形成与演化、银河系三维结构与动力学研究的关键性突破。

本项目研究按照原计划执行。对四颗致密天体双星进行了动力学质量测量，两颗发表在Nature杂志，一颗即将发表在Nature杂志，一颗发表在ApJ杂志。基于LAMOST光谱数据，构建了恒星和白矮星数据库，包括恒星紫外辐射星表，恒星X射线辐射星表，DA、DB型白矮星和白矮星主序双星星表。开发机器学习的方法，并运用到天文观测大数据中。同时，在理论研究方面取得了多项成果，系统研究黑洞/中子星X射线双星和白矮星双星的形成和演化机制，为观测现象提供理论模型支撑。在Nature，ApJ，MNRAS，A&A，PASP和RAA上共发表论文105篇，在New Astronomy Reviews和天文学进展上各发表1篇综述论文。