A number of spectroscopic surveys have been carried out or are planned to study the origin of the Milky Way. Their exploitation requires reliable automated methods and softwares to measure the fundamental parameters of the stars. Adopting the ULySS package,we have tested the effect of different resolutions and signal-tonoise ratios(SNR) on the measurement of the stellar atmospheric parameters(effective temperature Teff,surface gravity log g,and metallicity [Fe/H]) . We show that ULySS is reliable for determining these parameters with medium-resolution spectra(R ～2000) . Then,we applied the method to measure the parameters of 771 stars selected in the commissioning database of the Guoshoujing Telescope(LAMOST) . The results were compared with the SDSS/SEGUE Stellar Parameter Pipeline(SSPP) ,and we derived precisions of 167 K,0.34dex,and 0.16dex for Teff,log g and [Fe/H] respectively. Furthermore,120 of these stars are selected to construct the primary stellar spectral template library(Version 1.0) of LAMOST,and will be deployed as basic ingredients for the LAMOST automated parametrization pipeline.
This paper presents a novel spectroscopic method for searching for supernova candidates from massive galaxy spectra,which is expected to be applied to the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST).This method includes mainly five steps.The first step is spectral preprocessing,including removing spectral noise using wavelet transform,spectral de-redshift,etc.The second step is decomposition of galactic spectra;we can get the galaxy component and supernova component and calculate the Supernova Statistical Characterization Vector (SNSCV) of each galaxy spectrum.The third step is to decrease samples in all the galaxy spectral datasets according to SNSCV of each spectrum,and to use the LOF (Local Outlier Factor)-based outlier detection algorithm to obtain the preliminary selected spectral data.The fourth step is template matching by cross-correlation,according to the matched results we get the secondary selected spectral data.Finally,we choose the final supernova candidates manually through checking the spectral features characteristic of a supernova.By the spectroscopic method proposed in this paper,thirty-six supernova candidates have been detected in a dataset including 294843 galaxy spectra from the Sloan Digital Sky Survey Data Release 7.Nine of these objects are detected first and the other twenty-seven have been reported in other publications (fifteen of which are detected and reported first by us).The twenty-four new super-nova candidates include twenty Ia type supernova candidates,three Ic type supernova candidates and one II type supernova candidate.
TU LiangPing1,2,3*,LUO ALi2,WU FuChao1 & ZHAO YongHeng2 1 Institute of Automation,Chinese Academy of Sciences,Beijing 100190,China
The spatial distributions of old neutron stars (NSs) with ages 109 to 1010 yr in our Galaxy are investigated by Monte Carlo simulation under two different initial random velocity models.It is found that the scale heights of the distribution increase with the Galactic radial distance.The location of the peak of the NS distribution is closer to the Galactic center than that of their progenitors.The results from our detailed numerical analysis reveal that there is resemblance between the simulated old NS distribution and the structure of the observed HI disk.
WEI YingChun1,ZHANG ChengMin1,WU XinJi2,3*,ZHAO YongHeng1,CHOU ChiKang1 & LUO ALi1 1National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100012,China
以我国古代著名天文学家命名的大天区面积多目标光纤光谱天文望远镜"郭守敬望远镜"(LAMOST)是我国也是世界上光谱获取率最高的望远镜。LAMOST观测控制系统(Observatory Control System,OCS)负责执行观测流程,统一协调观测过程中各子系统,并记录相关信息。在软件设计中,按照观测控制流程的需求,以网络控制系统的方式实现了分布性、实时性、可靠性和开放性的观测控制。本文介绍LAMOST观测控制系统软件的功能要求、总体设计和软件实现,并以数据采集CCDMaster(相机集总控制)为例,详述了观测控制系统的运行过程,并对观测控制系统的难点、改进升级和对可能出现的问题的措施进行了描述。
