• South Galactic Cap u-band Sky Survey (SCUSS): Data Release

    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

  • The Large Sky Area Multi-Object Fiber Spectroscopic Telescope Quasar Survey: Quasar Properties From The First Data Release

    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

  • South Galactic Cap u-band Sky Survey (SCUSS): Data Reduction

    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