分类: 天文学 >> 天文仪器与技术 提交时间: 2016-04-27
摘要: AstroCloud is a cyber-Infrastructure for Astronomy Research initiated by Chinese Virtual Observatory (China-VO) under funding support from NDRC (National Development and Reform commission) and CAS (Chinese Academy of Sciences)1(Cui et al. 2014). To archive the astronomical data in China, we present the implementation of the astronomical data archiving system (ADAS). Data archiving and quality control are the infrastructure for the AstroCloud. Throughout the data of the entire life cy- cle, data archiving system standardized data, transferring data, logging observational data, archiving ambient data, And storing these data and metadata in database. Quality control covers the whole process and all aspects of data archiving.
分类: 天文学 >> 天文仪器与技术 提交时间: 2016-04-27
摘要: AstroCloud is a cyber-Infrastructure for Astronomy Research initiated by Chinese Virtual Observatory (China-VO) under funding support from NDRC (Na- tional Development and Reform commission) and CAS (Chinese Academy of Sci- ences). Tasks such as proposal submission, proposal peer-review, data archiving, data quality control, data release and open access, Cloud based data processing and analyz- ing, will be all supported on the platform. It will act as a full lifecycle management system for astronomical data and telescopes. Achievements from international Virtual Observatories and Cloud Computing are adopted heavily. In this paper, backgrounds of the project, key features of the system, and latest progresses are introduced.
分类: 天文学 >> 天体物理学 提交时间: 2016-05-05
摘要: The Large sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) general survey is a spectroscopic survey that will eventually cover approximately half of the celestial sphere and collect 10 million spectra of stars, galaxies and QSOs. Objects in both the pilot survey and the first year regular survey are included in the LAMOST DR1. The pilot survey started in October 2011 and ended in June 2012, and the data have been released to the public as the LAMOST Pilot Data Release in August 2012. The regular survey started in September 2012, and completed its first year of operation in June 2013. The LAMOST DR1 includes a total of 1202 plates containing 2 955 336 spectra, of which 1 790 879 spectra have observed signalto-noise ratio (SNR) ≥ 10. All data with SNR ≥ 2 are formally released as LAMOST DR1 under the LAMOST data policy. This data release contains a total of 2 204 696 spectra, of which 1 944 329 are stellar spectra, 12 082 are galaxy spectra and 5017 are quasars. The DR1 not only includes spectra, but also three stellar catalogs with measured parameters: late A,FGK-type stars with high quality spectra (1 061 918 entries), A-type stars (100 073 entries), and M-type stars (121 522 entries). This paper introduces the survey design, the observational and instrumental limitations, data reduction and analysis, and some caveats. A description of the FITS structure of spectral files and parameter catalogs is also provided.
分类: 天文学 >> 天文仪器与技术 提交时间: 2016-05-05
摘要: We present seeing measurements of the Guoshoujing Telescope (formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope- LAMOST) site at Xinglong station during the period from 2007 March 12 to April 25. The measurements were carried out with the Differential Image Motion Monitor (DIMM), and a total of 9259 data sets was obtained. The median seeing was measured to be 1.1″, with 25% being better than 0.8″and 75% better than 1.5″. The experiment shows that the DIMM exposure time has significant effects on the results of seeing measurements. An SBIG Polaris seeing monitor, which had been planned to be installed on the LAMOST site for long-term monitoring, was also employed during the DIMM observations. The results show that the SBIG seeing monitor is easily affected by gusty wind, resulting in larger seeing values. Considering the previous seeing measurements at Xinglong station over the last 15 yr, we conclude that an acceptable seeing condition at Xinglong station is around 1″–2″.
分类: 天文学 >> 天体物理学 提交时间: 2016-05-05
摘要: The South Galactic Cap u-band Sky Survey (SCUSS) is a deep u-band imaging survey in the Southern GalacticCap, using the 90Prime wide-field imager on the 2.3 Bok telescope at Kitt Peak. The survey observations started in2010 and ended in 2013. The final survey area is about 5000 deg2 with a median 5σ point source limitingmagnitude of ?23.2. This paper describes the survey data reduction process, which includes basic imagingprocessing, astrometric and photometric calibrations, image stacking, and photometric measurements. Surveyphotometry is performed on objects detected both on SCUSS u-band images and in the SDSS database. Automatic,aperture, point-spread function (PSF), and model magnitudes are measured on stacked images. Co-added aperture,PSF, and model magnitudes are derived from measurements on single-epoch images. We also present comparisonsof the SCUSS photometric ca
分类: 天文学 >> 天文仪器与技术 提交时间: 2016-05-05
摘要: Although the roles of data centers and computing centers are becoming more and more important, and on-line research is becoming the mainstream for astronomy, individual research based on locally hosted data is still very common. With the increase of personal storage capacity, it is easy to find hundreds to thousands of FITS files in the personal computer of an astrophysicist. Because Flexible Image Transport System (FITS) is a professional data format initiated by astronomers and used mainly in the small community, data management toolkits for FITS files are very few. Astronomers need a powerful tool to help them manage their local astronomical data. Although Virtual Observatory (VO) is a network oriented astronomical research environment, its applications and related technologies provide useful solutions to enhance the management and utilization of astronomical data hosted in an astronomer’s personal computer. FITSManager is such a tool to provide astronomers an efficient management and utilization of their local data, bringing VO to astronomers in a seamless and transparent way. FITSManager provides fruitful functions for FITS file management, like thumbnail, preview, type dependent icons, header keyword indexing and search, collaborated working with other tools and on-line services, and so on. The development of the FITSManager is an effort to fill the gap between management and analysis of astronomical data.
分类: 天文学 >> 天体物理学 提交时间: 2016-05-05
摘要: We present preliminary results of the quasar survey in the Large Sky Area Multi-Object Fiber SpectroscopicTelescope (LAMOST) first data release (DR1), which includes the pilot survey and the first year of the regularsurvey. There are 3921 quasars reliably identified, among which 1180 are new quasars discovered in the survey.These quasars are at low to median redshifts, with a highest z of 4.83. We compile emission line measurementsaround the Hα, Hβ, Mg II, and C IV regions for the new quasars. The continuum luminosities are inferred fromSDSS photometric data with model fitting, as the spectra in DR1 are non-flux-calibrated. We also compile the virialblack hole mass estimates, with flags indicating the selection methods, and broad absorption line quasars. Thecatalog and spectra for these quasars are also available. Of the 3921 quasars, 28% are independently selected withop
分类: 天文学 >> 星系和宇宙学 提交时间: 2016-05-05
摘要: The South Galactic Cap u-band Sky Survey (SCUSS) is a deep u-band imaging survey in the south Galactic capusing the 2.3 m Bok telescope. The survey observations were completed at the end of 2013, covering an area ofabout 5000 square degrees. We release the data in the region with an area of about 4000 deg2 that is mostly coveredby the Sloan digital sky survey. The data products contain calibrated single-epoch images, stacked images,photometric catalogs, and a catalog of star proper motions derived by Peng et al. The median seeing and magnitudelimit (5σ) are about 2 0 and 23.2 mag, respectively. There are about 8 million objects having measurements ofabsolute proper motions. All the data and related documentations can be accessed through the SCUSS data releasewebsite http://batc.bao.ac.cn/Uband/data.html.Key words: catalogs – surveys – techniques: image processing – techni
分类: 天文学 >> 天文学 提交时间: 2016-05-23
摘要: The Five-hundred-meter Aperture Spherical radio Telescope (FAST) will begin its early-science operations during 2016. Drift-scan pulsar surveys will be carried out during this period using an ultra-wide-band receiver system (covering ∼ 270 to 1620 MHz). We describe a method for accounting for the changes in the telescope beam shape and the pulsar parameters when searching for pulsars over such a wide bandwidth. We applied this method to simulated data sets of pulsars in globular clusters that are visible to FAST and found that a representative observation would have a sensitivity of ∼ 40 µJy. Our results showed that a single drift-scan (lasting less than a minute) is likely to find at least one pulsar for observations of four globular clusters. Repeated observations will increase the likely number of detections. We found that pulsars in ∼16 clusters are likely to be found if the data from 100 drift-scan observations of each cluster are incoherently combined.
分类: 物理学 >> 基本粒子与场物理学 分类: 物理学 >> 地球物理学、天文学和天体物理学 提交时间: 2016-06-16
摘要: 洛伦兹变换的时间膨胀是真实的物理效应还仅是数学的等效关系?本文提出一种独立实验方案,可在实验室坐标系比较和鉴别狭义相对论与 Lienard-Wiechert 推迟电磁场理论的物理真实性。 令一个高速运动电荷先后穿越两个相邻的皆配置有电场仪的屏蔽室;一方面可根据两种时空观分别计算出‘运动电荷的位置随时间变化’的理论曲线;另一方面可根据电场仪记录准确判断‘电荷位于第一个屏蔽室或第二个屏蔽室的时段’。将关于电荷位置的两条理论曲线与电场仪记录的实验曲线比较,即可判定何种理论符合自然实际。
分类: 天文学 >> 天文学 提交时间: 2016-11-15
摘要: With the development of network and the World Wide Web (WWW), the Internet has been growing and changing dramatically. More and more on-line database systems and different kinds of services are available for astronomy research. How to help users find their way through the jungle of information services becomes an important challenge. Although astronomers have been aware of the importance of interoperability and introduced the concept of Virtual Observatory as a uniform environment for future astronomical on-line resources and services, transparent access to heterogeneous on-line information is still difficult.
分类: 天文学 >> 天文学 提交时间: 2016-11-15
摘要: Not only source catalogs are extracted from astronomy observations. Their sky coverage is always carefully recorded and used in statistical analyses, such as correlation and luminosity function studies. Here we present a novel method for catalog matching, which inherently builds on the coverage information for better performance and completeness. A modified version of the Zones Algorithm is in-troduced for matching partially overlapping observations, where irrelevant parts of the data are excluded up front for efficiency. Our design enables searches to focus on specific areas on the sky to further speed up the process. Another im-portant advantage of the new method over traditional techniques is its ability to quickly detect dropouts, i.e., the missing components that are in the observed regions of the celestial sphere but did not reach the detection limit in some observations. These often provide invaluable insight into the spectral energy dis-tribution of the matched sources but rarely available in traditional associations.
分类: 天文学 >> 天文学 提交时间: 2016-11-16
摘要: The Large sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is the largest optical telescope in China. In last four years, the LAMOST telescope has published four editions data (pilot data release, data release 1, data release 2 and data release 3). To archive and release these data (raw data, catalog, spectrum etc),we have set up a data cycle management system, including the transfer of data, archiving,backup. And through the evolution of four software versions, mature established data release system.
分类: 天文学 >> 天文学 提交时间: 2016-11-16
摘要: As the cyber-infrastructure for Astronomical research from Chinese Virtual Observatory (China-VO) project, AstroCloud has been archived solid progresses during the last one year. Proposal management system and data access system are redesigned. Several new sub-systems are developed, including China-VO PaperData, AstroCloud Statics and Public channel. More data sets and application environments are integrated into the platform. LAMOST DR1, the largest astronomical spectrum archive was released to the public using the platform. The latest progresses will be introduced.
分类: 天文学 >> 天文学 提交时间: 2016-11-16
摘要: 本文提出了一种天象厅环境下的座席区设计方法,该方法将天象厅中的观众体验感分为五类,将感官体验量化,分别进行数学建模,然后将五个模型根据比重综合,得到天象厅中体验感的数学模型,对其进行分析得出较优的座席区范围,并引入偏转角变量设计了固定座席区与旋转座席区。并针对天象厅超大垂直面视野设计了一种座椅,该座椅能舒适地为观众提供较大的仰角观看节目
分类: 天文学 >> 天文学 提交时间: 2016-11-16
摘要: VOFilter is an XML based filter developed by the Chinese Virtual Observatory project to transform tabular data files from VOTable format into OpenDocument format. VOTable is an XML format defined for the exchange of tabular data in the context of the Virtual Observatory (VO). It is the first Proposed Recommendation defined by International Virtual Observatory Alliance, and has obtained wide support from both the VO community and many Astronomy projects. OpenOffice.org is a mature, open source, front office applications suite with the advantage of native support of industrial standard OpenDocument XML file format. Using the VOFilter, VOTable files can be loaded in OpenOffice.org Calc, a spreadsheet application, and then displayed and analyzed as other spreadsheet files. Here, the VOFilter acts as a connector, bridging the coming VO with current industrial office applications. Virtual Observatory and technical background of the VOFilter are introduced. Its workflow, installation and usage are presented. Existing problems and limitations are also discussed together with the future development plans.
分类: 天文学 >> 天文学 提交时间: 2016-11-16
摘要: 目前,虚拟天文台已经成为世界天文学界乃至 IT 界的热门话题。美国、欧盟、英国的虚拟天文台计划已经进入实施阶段,更多国家的类似计划正在酝酿之中,国际虚拟天文台联盟初现端倪。如此形势之下,中国为什么有必要建立自己的虚拟天文台?中国虚拟天文台将有何特色,对国际虚拟天文台会有怎样的贡献?中国虚拟天文台将采用何种体系结构,何时能实现?本文就这些问题进行了探讨。
分类: 天文学 >> 天文学 提交时间: 2016-11-16
摘要: 四百年前伽利略发明了天文望远镜,使人类首次摆脱了用肉眼直接观测天空的历史,为从哥白尼开始的天文学革命提供了大量的科学证据。历史悠久的天文学经过哥白尼、伽利略、开普勒和牛顿等人的发展,演变成了一门崭新的科学,同时也催生了现代科学技术。
分类: 物理学 >> 核物理学 分类: 物理学 >> 地球物理学、天文学和天体物理学 提交时间: 2016-11-25
摘要: Changes in beam position within charged particle accelerator storage rings have been observed due to changes in gravity (Δg) caused by the moon and sun. The terrestrial tidal model has been used to explain this type of beam instability. Further analysis reveals that these instabilities arise from changes in the electron beam energy, rather than from movements of the accelerator components due to terrestrial tidal forces. We suggest a potential model to better explain this type of instability. Consider a charged particle beam ring rotating with the earth, perpendicular to the moon's line of gravity. We induce an electromotive force along the ring, referred to as electro-gravitational induction (EGI). The circular motion of the charged particles causes the accumulation of the EGI in the storage ring, turn by turn. We used existing data from storage ring beam signals to estimate the maximum value of the gravity coefficient of the induced electromotive force.
分类: 物理学 >> 地球物理学、天文学和天体物理学 分类: 物理学 >> 原子与分子物理学 提交时间: 2016-12-10
摘要: 通常的狭义相对论是在庞加莱变换下不变的,它的基本度规为闵科夫斯基时空度规,该度规满足没有宇宙学常数Λ的真空爱因斯坦方程。本文指出:Λ≠0 时的狭义相对论是德西特/反德西特不变狭义相对论。求解Λ≠0的真空爱因斯坦方程,得到这种拓展的狭义相对论的基本度规是陆启铿-邹振隆-郭汉英1974年提出的Beltrami 度规;用欧拉-拉格朗日方程证明Beltrami时空的自由粒子运动是惯性运动。本文求出了德西特/反德西特不变狭义相对论的全部凯林(Killing) 矢量,证明了Beltrami 时空是最大对称性空间。导出来全部守恒量。构造了理论的正则形式,发现了正、负正则能量的色散关系的不对称性;实现了正则量子化,导出了相对论性波方程,从而建立了德西特/反德西特不变的相对论量子力学。简要介绍了通过天文观测原子(或离子)能级劈裂来探测精细结构常数#11;改变的实验。实验结果在4 ∼ 5σ 置信度内否定了庞加莱不变狭义相对论的预言,发现在z ≈ {1 ∼ 3}处αz ̸= α0。由于原子或离子能级的精细结构是相对论量子力学的结果,所以观测实验支持在红移z ≥ 1的狭义相对论量子力学中的Λ修正不可忽略。这是对德西特/反德西特不变狭义相对论的实验支持。是超出现有物理学标准模型的新物理。