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 >> 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： 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： 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 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.
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