An Asymmetric Galactic Stellar Disk Traced by OB-type Stars from LAMOST DR7

作     者：Xiaopeng Liu Hao Tian Wenyuan Cui Linlin Li Jiaming Liu Zhenyan Huo Yawei Gao 

作者机构：Department of PhysicsHebei Normal UniversityShijiazhuang 050024China Guo Shoujing Institute for AstronomyHebei Normal UniversityShijiazhuang 050024China Key Laboratory of Space Astronomy and TechnologyNational Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Institute for Frontiers in Astronomy and AstrophysicsBeijing Normal UniversityBeijing 102206China 

出 版 物：《Research in Astronomy and Astrophysics》 (天文和天体物理学研究（英文版）)

年 卷 期：2024年第24卷第6期

页      面：38-51页

核心收录：

学科分类：07[理学] 070401[理学-天体物理] 0704[理学-天文学] 

基　　金：supported by the National Natural Science Foundation of China(NSFC,grant Nos.12173013,12103062,12003045,and 11903012) the National Key Basic R&D Program of China via 2019YFA0405500 supported by the Natural Science Foundation of Hebei Province under grant A2021205006 and A2019205166 by the project of the Hebei provincial department of science and technology under grant number 226Z7604G the science research grants from the China Manned Space Project 

主　　题：Galaxy:disk galaxies:spiral stars:early-type stars:massive 

摘      要：Using 9943 OB-type stars from LAMOST DR7 in the solar neighborhood,we fit the vertical stellar density profile with the model including a single exponential distribution at different positions(R,Φ).The distributions of the scale heights and scale length show that the young disk traced by the OB-type stars is not *** scale length decreases versus the azimuthal angleΦ,i.e.,from.■kpc withΦ=-3°to■kpc withΦ=9°.Meanwhile we find signal of non-symmetry in the distribution of the scale height of the north and south of the disk *** scale height in the north side shows signal of flaring of the disk,while that of the south disk stays almost constant around h_(s)=130 *** distribution of the displaceeent of the disk plane Z_(0)also shows variance versus the azimuthal angleΦ,which displays significant differences with the warp model constrained by the Cepheid *** also test different values for the position of the Sun,and the distance between the Sun and the Galactic center affects the scale heights and the displacement of the disk significantly,but that does not change our conclusion that the disk is not axisymmetric.