1 / 26

Performance and sensitivity of Low Resolution Spectrographs for LAMOST

Performance and sensitivity of Low Resolution Spectrographs for LAMOST. Zhu Yongtian, Hou Yonghui, Hu Zhongwen Wang Lei, Wang Jianing San Diego, 27 June, 2010. Outline. Brief introduction -- LAMOST -- LRSs Test results

mahdis
Download Presentation

Performance and sensitivity of Low Resolution Spectrographs for LAMOST

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Performance and sensitivity of Low Resolution Spectrographs for LAMOST Zhu Yongtian, Hou Yonghui, Hu Zhongwen Wang Lei, Wang Jianing San Diego, 27 June, 2010

  2. Outline • Briefintroduction --LAMOST --LRSs • Test results -- Image quality -- Throughout --Wavelength coverage and resolution • Some results in early commissioning observation

  3. LAMOST

  4. Specification of LAMOST • Effective aperture: D = 4m • Focal ratio: F#= 5 • field of view : 5 degrees • Number of Fibers : 4000 • FRD: f/5→f/4 • Fiber core diameter: 320micons or 3.3″

  5. Specification of Low Resolution Spectrograph • There are 16 LRS spectrographs • 250 fibers for each spectrograph • Wavelength coverage 370nm~900nm • Resolution expected 1000~10000

  6. Blue band(370~590nm) R5000/10000 R1000/2000 Red band (570~900nm) R5000/10000 R1000/2000 Yongtian Zhu, Zhongwen Hu, Qingfeng Zhang, et al. Proc. SPIE 6269(2006) The optical layout of the LAMOST-LRS

  7. Spectrograph Parameters • 16 low resolution spectrographs (LRSs) for LAMOST • 250 fibers(3.3 arcsecs) / Each spectrograph • The fibers are separated by 578μm center to center along the 144 mm heightarc slit • F/4 Schmidt collimator • A dichroic beam-splitter • 4 VPH gratings/LRS (low, and medium dispersion respectively) • 2 articulating red and blue F/1.3 Schmidt cameras • field lens • Corrector mirrors • 4096×4136 EEV CCD 12μm square pixel size

  8. In laboratory in Xinglong Station

  9. VPH Grating sets of LAMOST-LRS

  10. VPHG

  11. VPH gratings wavefront quality

  12. Resolution powers • Low-resolution mode • 3700 – 9000 Å R ~ 1000 / 2000 • Medium-resolution mode • 5100 – 5500 Å 8300 – 8900 Å • R ~ 5000 / 10000

  13. 32 CCD Detectors • E2V / England • Chinese Company

  14. Image quality of blue band for low resolution configurationR=1000

  15. Image quality of red band for low resolution configuration (R=1000)

  16. Image quality for medium resolution configuration (R=5000)

  17. Image quality

  18. Image quality (with 1.6″slit) • two dimensional spectra of arc lamp (with 1.6″slit)

  19. Throughput • Throughput of LAMOST-LRS without considering the CCD quantum efficiency and fiber transmission loss

  20. Wavelength coverage and resolution • CCD can cover about 348nm(red band),234nm (blue band) • The wavelength range: 365-599nm (blue band) • 565-913nm(red band) • The resolution at central wavelength: • 1100 (at 740nm), 1040 (at 480nm) • The 1D spectrum of arc lamp

  21. Blue band Red band The twilight sky spectra obtained by LAMOST

  22. Some observation results during the early commissioning phase (in the winter 2009) • A very bright i = 16.44 quasar in the ‘redshift desert’ discovered by LAMOST (Xue-Bing Wu1, Zhaoyu Chen1, Zhendong Jia et al.)(2010) • Eight new quasars discovered by LAMOST in one extragalatic field(Xue-Bing Wu, Zhendong Jia, Zhaoyu Chen et al.) (2010) • LAMOST Discovers Quasars Behind the AndromedaGalaxy(Zhi-Ying Huo, Xiao-Wei Liu, Hai-Bo Yuan et al.)(2010) • Detection of New Candidates of Metal-poor Stars with LAMOST Commissioning Data(H.-N. Li, G. Zhao, N. Christlieb) (2010) • LAMOST Discovers New Planetary Nebulae in the Outskirts of the Andromeda Galaxy(Hai-Bo Yuan, Xiao-Wei Liu, Zhi-Ying Huo ) (2010) • ……………………………………

  23. A very bright i = 16.44 quasar in the ‘redshift desert’ discovered by LAMOST (z=2.427) • Left panel: The LAMOST spectrum of SDSS J085543.40-001517.7. Right panel: The spectrum of SDSS J085543.40-001517.7 taken by the NAOC/Xinglong 2.16m telescope. The scaled SDSS composite quasar spectrum (in red color) is shown for comparison Xue-Bing Wu, Zhaoyu Chen, Zhendong Jia et al. 2010 accepted by RAA

  24. Eight new quasars • 8 new quasars ( 2 quasars in the redshift desert) • i magnitudes: 16.24 to 19.10 • z (redshift) 0.898 to 2.773 Xue-Bing Wu, Zhendong Jia, Zhaoyu Chen et al. 2010 accepted by RAA

  25. Detection of New Candidates of Metal-poor Stars with LAMOST • only the LAMOST blue arm spectra are shown, and the continuum has not been subtracted. Hai-Bo Yuan, Xiao-Wei Liu, Zhi-Ying Huo, et al. 2010 accepted by RAA

  26. Thank You！ ytzhu@niaot.ac.cn

More Related