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Nov 26, 2009 Chongqing

NAOC and Steward Observatory The South Galactic Cap U-band Sky Survey with the Bok 2.3m Telescope. Fan Zhou NAOC. Nov 26, 2009 Chongqing. Why do we need the survey?. To supply the input source catalogue for LAMOST;

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Nov 26, 2009 Chongqing

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  1. NAOC and Steward Observatory The South Galactic Cap U-band Sky Survey with the Bok 2.3m Telescope Fan Zhou NAOC Nov 26, 2009 Chongqing

  2. Why do we need the survey? • To supply the input source catalogue for LAMOST; • To classify of the stars, galaxies, AGN and quasars in the south Galactic cap region with the color-color diagram; • To detect the red shift z<3 quasar candidates combining the photometry in other bands; • To estimate the red shift of the galaxies with PhotoZ combining the photometry in other bands; • To find out some starburst galaxies candidates; • It can help us estimate the metallicity of the stellar populations in the galaxies; • To identify the type of the stars in the color-color diagram combining the photometry in other bands, which can help us the control the completeness of the star type for the LAMOST observations; • It can be helpful for the flux calibration of the LAMOST spectra.

  3. Science 图1：SDSS测光中的恒星（×），星系（△）和类星体（其中红移z< 3.5的源用□表示，红移z≥ 3.5的源用■表示）的双色图。 图2：不同类型的恒星在双色图上的位置是不同的

  4. Science • 图2：1个太阳质量，年龄是1 Gyr的谱能量分布随金属丰度的变化。 • 图1：BC03模型中太阳金属丰度下星族的谱能量分布随年龄的变化。

  5. The Bok • Organization: Steward Observatory. • Location: Kitt Peak, Arizona, USA • Wavelength: optical, infrared • Diameter: 2.3m (90 inches)

  6. Location―Kitt Peak • Altitude: 6,900 ft (2071 m) • Latitude: +31° 57' 46.5“ • Longitude: 111°36' 01.6"W • Time Zone: +7 hours

  7. The Telescope The Bok 90 inch (2.3 meter) Reflector Telescope

  8. Project Directors • PI: Xu Zhou(NAOC) • PI: Michael Lesser (SO/UA)

  9. Michael was working in the Lab…

  10. Control Room

  11. CCD Lab

  12. 1.SDSS Filters (u',g',r', i',z'-band) 2.New Johnson / Bessel Filters 3. Pan-STARRS Filter (g, r, i, z, y)

  13. CCD configuration

  14. The 5×5 Pointings

  15. CCD QE

  16. The U-band Sky MAP

  17. The U-band Sky Survey

  18. Flux Calibration Calibrationtime: 387×3min=21 hours

  19. Total Observation Time • If we have 55 nights: 55 nights ×10 hours / nights =550 hours • Each field: (550 hours×65% useful night -21)/3700=5.46 min • If we have 80 nights: 80 nights ×10 hours / nights =800 hours • Each field: (800 hours×65% useful night -21)/3700=8.09 min

  20. The Data Storage • For each pointing: 4×33Mb×3 times=0.4G • 3700 deg2 region=3700×0.4 G=1480 G • Flux calibration observations: 3700/9 × 4×33M×2 (Standard star and objects)=108.5 G • FLAT: 15 × 4 frames × 20 M × 80 Nights=96 G • BIAS:15 ×4 frames × 20 M × 80 Nights=96 G • Total Size=1781 G≈1.8 T • Catalogues: Point sources and extended sources? • We need the Database and Search like SDSS

  21. The Database • Finding chart, images, search,download,catalogs

  22. CSTAR Data Analysis---- Catalogue Release Zhou Xu , Fan Zhou, et al.

  23. Introduction • In Jan 2008 , Chinese Small Telescope ARray (CSTAR) was successfully mounted in the highest plateau of Antarctic - Dome A by the 24th Chinese expedition team. • CSTAR - four 14.5 cm telescopes g, r, i and white filters • FOV: 4.5 ◦ × 4.5◦ • The Dome A locates at 77◦0657E -80◦2508S (1271 km from Zhongshan Station. • The altitude ∼ 4093 meters • The temperature is quite low to −81◦C • the PWV of dome A is supposed to be only half of that in dome C • The median seeing of dome A should be less than 0.27. • The boundary layer thickness of dome A is ∼ 10 m which is much thinner than that of dome C.

  24. CSTAR#1 Observation Time There are 16918, 50575, 68157, 110357, 58711 and 5749 images in March, April, May, June, July and August, respectively. The total exposure time is 67.37, 311.39, 378.65, 613.09, 326.17 and 31.94 hours, respectively, in these months and the total exposure time is 1728.61 hours.

  25. Flux Calibration with USNO-B1

  26. Flux Calibration--Standard Stars Monet et al. (2003) derived the formula for transforming the magnitudes of USNO-B1.0 to the magnitudes in SDSS filters with ∼ 450 deg2 of SDSS Early Data Release <i CSTAR − i USNO>= 4.1561 ±0.1225 with 48 points.

  27. The Light Curve of A Bright Star A bright star of 10.1 mag (14h32m31.5s ,−87◦56 09.2 )

  28. The Magnitude Uncertainty Estimate

  29. Limiting Magnitude changing of One Day

  30. CSTAR#1 Catalogue Sample • The catalogue header: -59 2008 Jun 02 22:50:42.20 20 357 A 10398 • 154.954086 • NOTE-The header parameter mean: (1)-59: temperature (2)2008 Jun 02: date (3)20: exposure time in second (4) 357: sky light ADU value (5) 10398: • mag=10.398 (6) 154.954086 Julian time.The full catalogues can be downloaded on http://batc.bao.ac.cn/ zhouxu/.

  31. Thank you!

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