利用LAMOST数据研究银河系的三维消光分布、消光规律及星际弥散带

Constructing a three-dimentional extinction map of the Galaxy plays an essential role in studies of Galactic structure, distribution and properties of interstellar dust and many other fields. The nature and origins of diffuse interstellar bands (DIBs) are one of the most challenging problems in astronomical spectroscopy.With modern large scale spectroscopic surveys such as.SDSS and LAMOST, Galactic astronomy enters the era of millions of spectra. Therefore, we propose using the standard pair technique to measure extinction of a large sample of individual stars and using the "template subtraction" technique to detect and measure DIBs in millions of spectra. Both methods can apply to most types of stars and are insensitive to systematic errors of basic stellar parameters.Both methods have been tested and verified using the SDSS and available LAMOST data. By combining the LAMOST spectroscopic dataset with the Galex, SDSS, Xuyi, 2MASS and WISE photometric datasets, we will construct a three-dimentional multi-band extinction map of the Galactic plane at a high spatial resolution, and further study variations of extinction laws and dust properties as a function of positions and environments. We also expect to detect DIBs in hundreds of thousands LAMOST spectra. With such a huge database, we will study the demographical distribution, properties and nature of DIBs.

精确测量银河系三维多波段消光分布对获取天体内禀辐射性质、构建银河系三维结构、获取星际气体尘埃的分布及性质具有重要意义。星际弥散带(DIBs)的证认与起源是天文分光学的世纪难题。LAMOST海量数据则为获取天区覆盖范围和深度及空间采样密度都有量级上的提高的银盘尘埃消光、星际弥散带强度的三维空间分布，为研究星际尘埃性质、消光规律及星际弥散带的起源提供前所未有的机遇。利用申请人自主发展且经过SDSS数据验证的、通过恒星配对精确测量大样本恒星消光及利用光谱匹配较差在海量光谱中探测DIBs的方法，结合LAMOST光谱数据和多色测光数据，本项目将：1）构建银盘高分辨率的三维多波段消光与尘埃分布，并研究从紫外到中红外消光规律随空间、环境的变化；2）对星际弥散带的分布与性质进行大样本统计研究，并探讨其起源。

精确测量银河系三维多波段消光分布对获取天体内禀辐射性质、构建银河系三维结构、获取星际气体尘埃的分布及性质具有重要意义。星际弥散带(DIBs)的证认与起源是天文分光学的世纪难题。基于LAMOST、APOGEE海量光谱数据与恒星大气参数，结合Gaia的精确测光与距离数据，利用恒星配对方法，本课题对银河系尘埃及DIB的三维大尺度分布及尘埃的多波段消光规律进行了深入研究。主要结果包括：1）发现银河系的尘埃存在两个盘状结构，尘埃薄盘和尘埃厚盘，并可能分别与银河系中的分子氢盘和中性氢盘成协；2）发现DIB的三维分布与尘埃类似，也存在两个盘状结构，且强度与消光的比值在两个盘上存在明显差异；3）发现银晕中存在相当部分的尘埃云状结构；4）探测到了太阳系黄道带尘埃的消光特征；5）构建了M31和M33方向的银河系前景的二维消光图；6）测量了银河系尘埃从紫外到中红外不同波段的消光系数，并对部分波段精确测量了消光系数随恒星类型与消光量的变化。我们的结果对研究银河系尘埃的分布与性质，尘埃与其它组分的相互作用，DIB的起源，及对银河系恒星开展超高精度的消光改正具有重要意义。