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A study on universal observation control system and its application for LAMOST

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Research in Astronomy and Astrophysics 2021年第6期21卷 369-386页

作者： Zheng Wang Yuan Tian Jian Li zi-huang cao Yong-Heng Zhao Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

The observatory control system(OCS),a part of automated control of Large Sky Area MultiObject Fibre Spectroscopic Telescope(LAMOST),runs on the CentOS6 platform and implements the communication between modules based on Common Object Request Broker Architecture(CORBA).However,CORBA is complicated and has limited development support;moreover,the official support for CentOS6 has *** inherently has some shortcomings such as the over-concentration of control and the blocking of device status processing,which hinder the realization of automated observation control of ***,this study designs and implements a universal observation control system(UOCS)for optical *** UOCS takes the device command as the basic execution unit,controls the device execution logic using observation script,controls the observation logic by event-driven messaging,and realizes mutual decoupling between modules via a distributed control mode,thereby ensuring high system *** UOCS performs significantly better than OCS in terms of the observation performance,operator complexity,and communication ***,UOCS is applied to the automated control of some devices and subsystems in LAMOST *** will be applied to the automated observation control of Multi-channel Photometric Survey Telescope by 2021.

关键词： telescopes techniques:miscellaneous methods:observational instrumentation:miscellaneous

LAMOST CCD camera-control system based on RTS2

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Research in Astronomy and Astrophysics 2018年第5期18卷 69-82页

作者： Yuan Tian Zheng Wang Jian Li zi-huang cao Wei Dai Shou-Lin Wei Yong-Heng Zhao Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of SciencesBeijing 100101 China Computer Technology Application Key Lab of Yunnan Province Kunming University of Science and TechnologyKunming 650500 China University of Chinese Academy of Sciences Beijing 100049 China

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST） is the largest existing spectroscopic survey telescope, having 32 scientific charge-coupled-device（CCD） cameras for acquiring spectra. Stability and automation of the camera-control software are essential, but cannot be provided by the existing system. The Remote Telescope System 2 nd Version（RTS2） is an open-source and automatic observatory-control system. However, all previous RTS2 applications were developed for small telescopes. This paper focuses on implementation of an RTS2-based camera-control system for the 32 CCDs of LAMOST. A virtual camera module inherited from the RTS2 camera module is built as a device component working on the RTS2 framework. To improve the controllability and robustness, a virtualized layer is designed using the master-slave software paradigm, and the virtual camera module is mapped to the 32 real cameras of LAMOST. The new system is deployed in the actual environment and experimentally tested. Finally, multiple observations are conducted using this new RTS2-frameworkbased control system. The new camera-control system is found to satisfy the requirements for automatic camera control in LAMOST. This is the first time that RTS2 has been applied to a large telescope, and provides a referential solution for full RTS2 introduction to the LAMOST observatory control system.

关键词： telescopes - techniques imaging spectroscopy - methods observational - instrumentation detectors

Study on the off situ reconstruction of the core neutron field based on dual-task hybrid network architecture

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Nuclear Science and Techniques 2025年第1期36卷 175-191页

作者： Pei cao Hui Ding Cheng-Long cao zi-Hui Yang Guo-Min Sun School of Artificial Intelligence and Big Data Hefei UniversityHefei 230001China College of Electronic Engineering National University of Defense TechnologyHefei 230001China Institute of Nuclear Energy Safety Technology HFIPSChinese Academy of SciencesHefei 230027China

The off situ accurate reconstruction of the core neutron field is an important step in realizing real-time reactor *** existing off situ reconstruction method of the neutron field is only applicable to cases wherein a single region changes at a specified location of the ***,when the neutron field changes are complex,the accurate identification of the individual changed regions becomes challenging,which seriously affects the accuracy and stability of the neutron field ***,this study proposed a dual-task hybrid network architecture(DTHNet)for off situ reconstruction of the core neutron field,which trained the outermost assembly reconstruction task and the core reconstruction task jointly such that the former could assist the latter in the reconstruction of the core neutron field under core complex ***,to exploit the characteristics of the ex-core detection signals,this study designed a global-local feature upsampling module that efficiently distributed the ex-core detection signals to each reconstruction unit to improve the accuracy and stability of *** experiments were performed on the simulation datasets of the CLEAR-I reactor to verify the accuracy and stability of the proposed *** results showed that when the location uncertainty of a single region did not exceed nine and the number of multiple changed regions did not exceed ***,the reconstructed ARD was within 2%,RD_(max)was maintained within 17.5%,and the number of RD≥10%was maintained within ***,when the noise interference of the ex-core detection signals was within±2%,although the average number of RD≥10%increased to 16,the average ARD was still within in 2%,and the average RD_(max)was within 22%.Collectively,these results show that,theoretically,the DTHNet can accurately and stably reconstruct most of the neutron field under certain complex core changes.

关键词： Real-time reactor monitoring Core neutron field reconstruction Dual-task hybrid network architecture Global-local feature upsampling module

Radio stars observed in the LAMOST spectral survey

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Research in Astronomy and Astrophysics 2017年第10期17卷 67-82页

作者： Li-Yun Zhang Qiang Yue Hong-Peng Lu Xian-Ming L.Han Yong Zhang Jian-Rong Shi Yue-Fei Wang Yong-Hui Hou zi-huang cao College of Physics/Department of Physics and Astronomy Guizhou University Department of Physics and Astronomy Butler University Nanjing Institute of Astronomical Optics & Technology National Astronomical Observatories Chinese Academy of Sciences Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences

Radio stars have attracted astronomers＇ attention for several decades. To better understand the physics behind stellar radio emissions, it is important to study their optical behaviors. The LAMOST survey provides a large database for researching stellar spectroscopic properties of radio stars. In this work, we concentrate on their spectroscopic properties and infer physical properties from their spectra, such as stellar activity and variability. We mined big data from the LAMOST spectral survey Data Release 2 （DR2）, published on 2016 June 30, by cross-matching them with radio stars from FIRST and other surveys. We obtained 783 good stellar spectra with high signal to noise ratio for 659 stars. The criteria for selection were positional coincidence within 1.5＂ and LAMOST objects classified as stars. We calculated the equivalent widths （EWs） of the Ca II H＆K, HS, H＇7, H/3, Ha and Ca II IRT lines by integrating the line profiles. Using the EWs of the Ha line, we detected 147 active stellar spectra of 89 objects having emissions above the Ha continuum. There were also 36 objects with repeated spectra, 28 of which showed chromospheric activity variability. Furthermore, we found 14 radio stars emitting noticeably in the Ca II IRT lines. The low value of the EWs542/EWsags ratio for these 14 radio stars possibly alludes to chromospheric plage regions.

关键词： stars: chromosphere- stars: activity -- stars: radio -- stars: spectroscopic

Site testing campaign for the Large Optical/infrared Telescope of China:general introduction of the Daocheng site

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Research in Astronomy and Astrophysics 2020年第6期20卷 151-161页

作者： Teng-Fei Song Yu Liu Jing-Xing Wang Xue-Fei Zhang Shun-Qing Liu Ming-Yu Zhao Xiao-Bo Li Zhan-Chuan Cai Qi-Wu Song zi-huang cao Yu Ruan State Key Laboratory of Lunar and Planetary Science Macao University of Science and TechnologyMacaoChina Yunnan Observatories Chinese Academy of SciencesKunming 650216China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210008China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Army Engineering University of PLA Chongqing 400042China

The Daocheng site is one of the three candidate sites for the Large Optical/infrared Telescope(LOT)of *** was discovered by Yunnan Observatories during the survey of potential sites for the next-generation large-aperture solar telescopes of *** paper describes the overview of the site,the observation platform and the monitor *** addition,simple statistical results are presented(from November,2016 up to December,2017).Detailed data results can refer to the overview of LOT site testing and data analysis articles,which were published during the same period.

关键词： site testing LOT Daocheng site observation platform

The Velocity Aberration Effect of the CSST Main Survey Camera

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Research in Astronomy and Astrophysics 2024年第9期24卷 119-127页

作者： Hui-Mei Feng zi-huang cao Man ILam Ran Li Hao Tian Xin Zhang Peng Wei Xin-Feng Li Wei Wang Hugh RAJones Mao-Yuan Liu Chao Liu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Key Laboratory of Cosmic Rays(Tibet University) Ministry of EducationLhasa 850000China University of Chinese Academy of Sciences Beijing 100049China Technology and Engineering Center for Space Utilization Chinese Academy of SciencesBeijing 100094China Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Centre for Astrophysics University of HertfordshireHatfieldUK

In this study,we conducted simulations to find the geometric aberrations expected for images taken by the Main Survey Camera of the Chinese Space Station Telescope(CSST)due to its *** anticipated by previous work,our findings indicate that the geometric distortion of light impacts the focal plane's apparent scale,with a more pronounced influence as the size of the focal plane *** models suggest that the effect consistently influences the pixel scale in both the vertical and parallel *** apparent scale variation follows a sinusoidal distribution throughout one orbital *** reveal that the effect is particularly pronounced in the center of the Galaxy and gradually diminishes along the direction of ecliptic *** low ecliptic latitudes,the total aberration leads to about a 0.94 pixel offset(a 20 minute exposure)and a 0.26 pixel offset(a 300 s exposure)at the edge of the field of *** processings for the geometric effect during the CSST pre-and post-observation phases are presented.

关键词： astrometry telescopes Astronomical Instrumentation Methods and Techniques

A sample of metal-poor galaxies identified from the LAMOST spectral survey

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Research in Astronomy and Astrophysics 2017年第5期17卷 17-30页

作者： Yu-Long Gao Jian-Hui Lian Xu Kong Ze-Sen Lin Ning Hu Hai-Yang Liu En-Ci Wang zi-huang cao Yong-Hui Hou Yue-Fei Wang Yong Zhang CAS Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Scienceand Technology of China Hefei 230026 China School of Astronomy and Space Science University of Science and Technology of China Hefei 230026 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of SciencesBeijing 100012 China Nanjing Institute of Astronomical Optics & Technology National Astronomical Observatories Chinese Academyof Sciences Nanjing 210042 China

We present a sample of 48 metal-poor galaxies at z 〈 0.14 selected from 92 510 galaxies in the LAMOST survey. These galaxies are identified by their detection of the auroral emission line[OⅢ]λ4363 above the 3σ level, which allows a direct measurement of electron temperature and oxygen abundance. The emission line fluxes are corrected for internal dust extinction using the Balmer decrement method. With electron temperature derived from [OⅢ]λλ4959, 5007/[OⅢ]λ4363 and electron density from [SⅡ]λ6731/[SⅡ]λ6717, we obtain the oxygen abundances in our sample which range from 12 ＋ log（O/H） = 7.63（0.09 Z_⊙） to 8.46（0.6 Z_⊙）. We find an extremely metal-poor galaxy with 12 ＋ log（O/H） = 7.63 ± 0.01. With multiband photometric data from FUV to NIR and Hαmeasurements, we also determine the stellar masses and star formation rates, based on the spectral energy distribution fitting and Hα luminosity, respectively. We find that our galaxies have low and intermediate stellar masses with 6.39 ≤ log（M/M_⊙） ≤ 9.27, and high star formation rates（SFRs） with-2.18 ≤ log（SFR/M_⊙yr^（-1）） ≤ 1.95. We also find that the metallicities of our galaxies are consistent with the local T_e-based mass-metallicity relation, while the scatter is about 0.28 dex. Additionally,assuming the coefficient of α = 0.66, we find most of our galaxies follow the local mass-metallicity-SFR relation, but a scatter of about 0.24 dex exists, suggesting the mass-metallicity relation is weakly dependent on SFR for those metal-poor galaxies.

关键词： galaxies: abundances -- galaxies: evolution -- galaxies: starburst -- star formation

Peculiar in-plane velocities in the outer disc of the Milky Way

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Research in Astronomy and Astrophysics 2017年第11期17卷 45-58页

作者： Hai-Jun Tian Chao Liu Jun-Chen Wan You-Gang Wang Qiao Wang Li-Cai Deng zi-huang cao Yong-Hui Hou Yue-Fei Wang Yue Wu Yong-Heng Zhao China Three Gorges University Yichang 443002 China Max Planck Institute for Astronomy K6nigstuhl 17 D-69117 Heidelberg Germany Key Laboratory for Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Key Laboratory of Computational Astrophysics National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Nanjing Institute of Astronomical Optics & Technology National Astronomical Observatories Chinese Academy of Sciences Nanjing 210042 China

We present the peculiar in-plane velocities derived from LAMOST red clump stars, which are purified and separated by a novel approach into two groups with different ages. The samples are mostly contributed around the Galactic anti-center direction so that we are able to map the radial profiles of the radial and azimuthal velocities in the outer disc. From variations of the in-plane velocities with Galactocentric radius for the younger and older populations, we find that both radial and azimuthal velocities are not axisymmetric at 8 〈 R 〈 14 kpc. The two red clump populations show that the mean radial velocity is negative within R - 9 kpc and positive beyond. This is likely because of the perturbation induced by the rotating bar. The cross-zero radius, R -9 kpc, essentially indicates the rough location of the Outer Lindblad Resonance radius. Given the circular speed of 238 km s^-1, the pattern speed of the bar can be approximated as 45 km s^-1 kpc^-1. The young red clump stars show larger mean radial velocity than the old population by about 3km s^-1 between R-9 and 12kpc. This is possibly because the younger population is more sensitive to the perturbation than the older one. The radial profiles of the mean azimuthal velocity for the two populations show an interesting U-shape, i.e. at R 〈 ***, the azimuthal velocity declines with R by about 10km s^-1, while at R 〉 10.5 kpc it increases with R to 240 - 245 km s^-1. It is not clear why the mean azimuthal velocity shows this U-shape along the Galactic anti-center direction. Moreover, the azimuthal velocity for the younger population is slightly larger than that for the older one and the difference moderately declines with R. Beyond R0-12 kpc, the azimuthal velocities for the two populations are indistinguishable.

关键词： Galaxy: disc -- Galaxy: structure -- Galaxy: kinematics and dynamics -- Galaxy: stellar content -- stars: kinematics and dynamics

Mapping the Milky Way with LAMOSTⅠ:method and overview

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Research in Astronomy and Astrophysics 2017年第9期17卷 81-100页

作者： Chao Liu Yan Xu Jun-Chen Wan Hai-Feng Wang Jeffrey L.Carlin Li-Cai Deng Heidi Jo Newberg zi-huang cao Yong-Hui Hou Yue-Fei Wang Yong Zhang Key Lab of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China University of the Chinese Academy of Sciences Beijing 100049China LSST 933 North Cherry AvenueTucsonAZ 85721USA Department of Physics Applied Physics and AstronomyRensselaer Polytechnic InstituteTroyNY 12180USA Nanjing Institute of Astronomical Optics&Technology National Astronomical ObservatoriesChinese Academy of SciencesNanjing 210042China

We present a statistical method to derive the stellar density profiles of the Milky Way from spectroscopic survey data, taking into account selection effects. We assume the selection function, which can be altered during observations and data reductions, of the spectroscopic survey is based on photometric colors and magnitude. Then the underlying selection function for a line-of-sight can be recovered well by comparing the distribution of the spectroscopic stars in a color-magnitude plane with that of the photometric dataset. Subsequently, the stellar density profile along a line-of-sight can be derived from the spectroscopically measured stellar density profile multiplied by the selection function. The method is validated using Galaxia mock data with two different selection functions. We demonstrate that the derived stellar density profiles reconstruct the true ones well not only for the full set of targets, but also for sub-populations selected from the full dataset. Finally, the method is applied to map the density pro- files for the Galactic disk and halo, using the LAMOST RGB stars. The Galactic disk extends to about R = 19 kpc, where the disk still contributes about 10% to the total stellar surface density. Beyond this radius, the disk smoothly transitions to the halo without any truncation, bending or breaking. Moreover, no over-density corresponding to the Monoceros ring is found in the Galactic anti-center direction. The disk shows moderate north-south asymmetry at radii larger than 12 kpc. On the other hand, the R-Z tomographic map directly shows that the stellar halo is substantially oblate within a Galactocentric radius of 20 kpc and gradually becomes nearly spherical beyond 30 kpc.

关键词： methods: statistical -- Galaxy structure -- Galaxy disk - Galaxy halo - surveys LAMOST