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LAMOST

LAMOST. Yongheng Zhao (NAOC) Very Wide Field Surveys in the Light of Astro2010 Baltimore, 15 June 2011. A national large scientific project Started in 1997 Inauguration in October 2008 Checked and accepted by national government in June 2009 now in commissioning stage

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LAMOST

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  1. LAMOST Yongheng Zhao (NAOC) Very Wide Field Surveys in the Light of Astro2010 Baltimore, 15 June 2011

  2. A national large scientific project • Started in 1997 • Inauguration in October 2008 • Checked and accepted by national government in June 2009 • now in commissioning stage • Pilot survey will begin in October 2011

  3. Structure of LAMOST MA mirror (4.9m) 4000 Fiber Positioning units 4000Fibers MB mirror (6.1m) 16 Spectrographs 32 CCDs

  4. Characteristics of LAMOST A horizontal meridian reflecting Schmidt telescope with an active correcting plate • large field of view (5 deg) + large aperture (4m) • Active optics on thin-mirror & segmented mirrors • 4000 optical fibers on focal surface • Parallel controllable fiber positioning

  5. MB(6.1m)

  6. （July 13,2008) Segmented Active optics for 37 sub-mirrors of MB

  7. 24 sub-mirrors of MA (4.9m)

  8. （Sept. 10, 2008) Segmented and thin mirror active optics for 24 sub-mirrors of MA

  9. Image quality of LAMOST （Nov. 21, 2008) Image quality: d80<1 arcsec (0.3 arsec in best) Site seeing ~ 2 arcsec

  10. At 3.2 degree FOV FWHM < 2 arcsec (Apr.25, 2009) Image quality: 0.3-0.4 arcsec Seeing: 1.7-2 arcsec

  11. Telescope • Declination: -10 60 90 • Effective aperture: 4.9m 4.2m 3.6m • Field of view: 5 degree 3 degree • Seeing: 2-3 arcsec (dome + site)

  12. Instruments • 4000 Fibers (130km) • 4000 Fiber positioning units • 16 Spectrographs • 250 fibers per spectrograph • 32 4k x 4k CCD Cameras • E2V CCD chips

  13. Fiber positioning units Double arm scheme Focal plane Positioning unit with 2 step motors

  14. 4000 fiber positioning units S-H sensor for MA Guiding CCDs

  15. Positioning accuracy of 4000 fibers • 96% < 0.5 arcsec (50 microns)

  16. CCD3 CCD0 CCD2 CCD1 Coordinates • Coordinates of 4000 fibers on focal plane • Celestial coordinate with CCDs Focal plane: expansion <==> contraction (changing with temperature) Focal length: longer <==> shorter (moving of focal plane) Move 1-2 mm (focal length ~ 20m) Image quality is controlled by active optics per minutes

  17. Accuracy of fiber positions 1 sigma < 0.6 arcsec • 90%<1 arcsec • 50%<0.5 arcsec

  18. 16 spectrographs 250 fibers per spectrograph RL = 1800 (2/3 slit width) Spectral range: blue: 370—590nm red: 570—900nm

  19. Throughput 5% from atmosphere to CCDs

  20. 10%

  21. LAMOST software systems TCS Input catalog SSS OCS ICS DHS 2D pipeline 1D pipeline Data center Data manage

  22. Early Sciences • M31 area • Planetary nebulae in M31 • Kinematics + populations of M31 • Quasars beyond M31 • Quasars selected • Metal-poor stars selected

  23. M31 area

  24. M31 area Sep.11,2010

  25. Planetary Nebulae in M31 (Yuan et al. 2010) • 17 new PNs • 19 confirmed two exp. in Oct. & Dec. 2009

  26. Beyond M31:(Huo et al. 2010) 14 new QSOs：z<2

  27. Kinematics and Stellar Population of M31 galaxy (Zou et al. 2011) • BATC 19 colors • LAMOST 2 exp. Oct. & Dec. 2009

  28. 8 New QSOs(Wu et al. 2010) 1 exp. In Dec. 2009 A very bright (i=16.44) quasar in the ‘redshift desert’ UKIDSS (Y-K) + SDSS (g-z)

  29. Candidates of metal-poor stars (Li et al. 2010) • 19 with S/N>15 • 9 with [Fe/H]<-1

  30. (Wu et al. 2011) 1D Pipeline  • 8 MP stars 1: [Fe/H]~-2.7

  31. Plan in 2011 • Oct. 2011: • pilot spectroscopic survey • Improve continually • Fiber position • Efficiency of 16 spectrographs • Dome seeing

  32. Limit magnitude • S/N>10 • 1800s exposure • Seeing = 3” or 2” • g < 18.9， 19.3 • i < 19.0， 19.4

  33. Scientific objects of LAMOST • Structure and evolution of the Galaxy • discovery of spheroid substructure • identify smooth component of spheroid • constrain Galactic potential and dark matter • structure of thin/thick disks, including chemical abundance and kinematics • search for extremely metal poor stars • search for hypervelocity stars • survey OB stars and 3D extinction in Galaxy • globular cluster environments • properties of open clusters • complete census of young stellar objects across the Galactic plane

  34. Study of extra-galactic astrophysics and cosmology. • Studies of large-scale structure of universe • Baryon Acoustics Oscillations => Dark energy • Formation and evolution of galaxies • AGN physics • Accurately measure luminosity functions & star-formation rate densities with redshift & environment • Detailed studies of local low-luminosity galaxies

  35. Spectroscopic Surveys • Stellar survey (7.5 M objects) • Halo structure • Disk star + open clusters • Anti-galactic center • Extra-galactic survey (6.3 M objects) • Galaxy and QSO redshift survey • Swallow, deep, EMG, QSO

  36. Scheme of LAMOST Operation NAOC LAMOST Science Committee LAMOST Operation Center WG for Stellar survey Survey planning + Data processing Observation + Operation WG for Extra-galactic survey Equipment maintenance WG for LAMSOT performance

  37. LAMOST Science Committee • combine 2 survey plans • organize research groups • Data policy (SDSS-like) Contact to: Gang ZHAO (gzhao@bao.ac.cn) • LAMOST Operation Center • Pilot survey from Oct. 2011 • Regular survey will begin in 2012 Contact to: Yongheng ZHAO (yzhao@bao.ac.cn)

  38. Thank You！

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