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Stellar population Studies with LAMOST - Chen Bing -

Stellar population Studies with LAMOST - Chen Bing -. Contents Galactic structure & Evolution Related Projects (SDSS/SUGUE, RAVE, AAOmage, GAIA) Collaboration & Proposal. Galactic structure. Thin Disk color-magnitude diagram Hipparcos; Density law Double exponential

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Stellar population Studies with LAMOST - Chen Bing -

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  1. Stellar population Studies with LAMOST- Chen Bing - Contents • Galactic structure & Evolution • Related Projects (SDSS/SUGUE, RAVE, AAOmage, GAIA) • Collaboration & Proposal

  2. Galactic structure Thin Disk color-magnitude diagram Hipparcos; Density law Double exponential Scale length/Scale height 2250/350 pc Age=(0,10 Gyr), Fe/H =(0.01, -0.37 dex), d[Fe/H]/dR=-0.07 (SigmaU, sigmaV, sigmaW) up to (43, 27, 17) km/s, Vad up to 15 km/s Thick Disk color-magnitude diagram 47 Tuc; Density law Double exponential Scale length/scale height 3500/750 pc Age=11 Gyr, Fe/H = -0.78, d[Fe/H]/dR=0 (SigmaU, SigmaV, sigmaW) = (67, 51, 42) km/s, Vad= 53 km/s Halo color-magnitude diagram M13, density law Power law, Axial ratio=0.55 Age= 14 Gry, Fe/H=-1.78, d[Fe/H]/dR=0 (SigmaU, SigmaV, sigmaW) = (131, 106, 85) km/s, Vad= 226 km/s Bulge Stellar streams,Dark matter

  3. Stellar populations in the Galaxy A SDSS sample (run 752, 756), including 375693 objects Simulated CMD with thick disk scale height of 1300 and 580 pc, respectively

  4. Ages of Galactic disk and halo CMD for the Hipparcos data, Overlaid by isochrone fits Jimenez et al. 1998 Isochrones are plotted for the Ages, 8, 11, 13, 15 Gyr, and Matallicities [Fe/H] = -0.5, 0.0, 0.3 Globular cluster M4 Hansen et al., 2002 Age= 12.7 Gyr for M4

  5. Stars at the solar neighbourhood

  6. 2df kinematic survey-The Anglo Australian Old stellar population Survey- Using 2df multi-object spectrograph Spectral resolution 2.5 A Velocity accuracy is 15 km/s ~ 2000 stars B-V < 0.7 V = 17.0 –19.5

  7. 2df kinematic survey stars from a disrupted satellite galaxy ?

  8. Halo stream around the Milky way The peculiar main-sequence at a a distance of 11 kpc from the Sun in the direction of (l,b)=200,20)

  9. Halo stream around the Milky way 500 SDSS spectroscopic radial velocities Have been taken The tidal disruption of a galaxy By the Milky Way?

  10. Age-Metallicity-Kinematics at the solar neighborhood Edvardsson et al. 1993 189 F/G main sequence stars -1.0 < [Me/H] < 0.3 Stromgren photometry high resolution spectra from ESO 1.4 m & Mcdonald 2.7 m

  11. Local dark matter Creze et al. 1998 The local dynamical density comes out as 0.076 Msun/pc^3 The total mass density of stars and interstellar metter ~ 0.08 Msun/Pc^3 Conclusion: no room for disk shaped component of dark matter

  12. The Thick disk – Halo Interface 2df metallicities vs radial velocity

  13. Performance of survey telescope Telescope Aperture Field of View A* F Gemini 8.1 0.17 1.8 WHT 4.2 0.5 4.4 VLT 8.1 0.4 10 SDSS/SEGUE 2.4 2.5 36 2df/AAOmega 3.9 2.0 61 6df/RAVE 1.2 6.6 65 LAMOST 4.0 5.0 400

  14. SDSS Multi-object Spectrographs End-to-end system throughput, including the telescope The two SDSS spectrographs. The square Black openings accept the fiber optics Slitheads, 320 fibers each.

  15. SDSS Multi-object Spectrographs Number of spectrographs 2 Spectral resolution 1800 Blue Channel range 3900-6000 A Red Channel range 6000-9100 A Fiber inputs per spectrograph 320 Telescope aperture 2.5 m Fiber diameter 180 microns ( 3” ) SDSS science plate targets ~ 500 galaxies, 100 QSO, and 30 stars SDSS key project redshifts for 10^6 galaxies and 10^5 quasars

  16. SEGUE(Sloan Extension for Galactic underpinnings and Evolution) The proposed Observing Strategy • imaging ~ 3500 square degrees mostly at |b| < 30 • The spectroscopic targets from SDSS & SEGUE 170 well-selected sky directions Two plates in each field, one normal exposure plate, and one double-length plate to a limit of g=20.3

  17. SEGUE imaging and spectroscopic observing plan

  18. Allocation of fibers per plate pair • 25 White dwarfs • 175 Blue Horizontal Branch, F-turnoff stars • 375 G dwarfs • 200 K giant • 200 Low-metallicity candidates • 175 M and K dwarfs • 130 sky fibers and calibration standards To an accuracy RVs Teff log g [Fe/H] 7 km/s 100-150 K 0.3-0.5 dex 0.25-0.3 dex

  19. RAVE(Radial Velocity Experiment) Using the 1.2-m UK Schmidt telescope of the AAO, Observing strategy (use of the Ca-triplet at 8400-8750, RVs better than 2 km/s) • Pilot survey (2003-2005) bright-time at the 6df using the existing 150-fibre 6df system, 7” diameter • Main Survey (2006-2010) will use the proposed 2250 fibre system 50 million stars, magnitude limited (V=16), all sky survey looking for a northern counterpart

  20. AAOmega A 3.9 m telescope providing a general purpose spectroscopic facility AAOmega – multiple-object mode • Field of view 2 degrees • Number of fibres 350-392 • Angular size of fibre 2” • Wavelength range 3700 –9500 A • Peak system throughput (Blue/Red) 0.17/0.20 • Spectrl resolution 1300 – 8000 • Spectral resolution 3.5 A • Limiting mag B=22.0

  21. AAOmega Galaxy Science Still under investigation, proposal including • Large AAOmega + RAVE stellar population survey • Halo structures, Thick disk metallicity – kinematics • DM distribution Input Catalogues exist (2MASS, …) Complement SEGUE, LAMOST in the north ..

  22. GAIA – ESA only mission

  23. GAIA • Astrometry (V < 20) • Radial velocity ( V < 16-17) Third component of space motion • Photometry ( V < 20) A Complete survey, launch date 2010-2012, + 5 year observations, final catalog ~ 2018

  24. DIVAGerman national Space science mission • Magnitude limited all-sky surveys (V =15-16), a mission between Hipparcos & GAIA • DIVA and RAVE complement each other. permit to determine the full 6-D distribution • CANCELLED !! unable to close the funding gap of ~ 15 million EURO • A big loss for RAVE, and its science

  25. Collaboration & Proposal Spectroscopic surveys for stars are important (RAVE, AAOmega, SEGUE) RAVE 1) Have a clear Science goal, magnitude limited survey (V=16) 2) looking for a collaboration in north (LAMOST is an option) 3) Science quality is reduced after DIVA was cancelled 4) GAIA final catalog ~ 2018 AAOmega 1) A telescope comparable with LAMOST 2) Science goals not yet decided 3) A general facility for all sciences ,

  26. One Proposal • Observing all SDSS/SEGUE stellar objects between V=17~20 mag • 4000 Fibres/field * 7 fields/night * 200 nights/year • = 5.6 million stars/ year • It can be finished before the launch of GAIA (probably 2012) • Successful 2df kinematic survey • Data can serve the whole community in our lifetime • Stars observed include thin disk, thick disk, halo, stellar streams, … • many sciences can be done • possible collaboration with GAIA mission • ,

  27. Comments from Brian Yanny (SEGUE leader) “ I think this is an excellent project for LAMOST ” “I understand that the resolution might be a bit worse, but even if your resolution is R ~ 1000, you should be able to do radial velocities to 30 km/s, if one is careful about calibration” “I would push them to think about their resolution and calibration schemes on their LAMOST spectrograph so that they may be able to get good radial velocities for many stars ” “I agree that LAMOST will be especially unique in getting velocities of faint stars, down to 20th magnitude or so, and in that way be complementary to a project such as GAIA which will get spectra for only brighter objects” ,

  28. My traces abroad 1989-1993, Ph.D, SIMBAD/CDS, France multi-color star count survey 1994-1999, Postdoc, Barcelona Spain Hipparcos & GAIA 1999-2001, SDSS, Johns Hopkins USA SDSS 2001-now, XMM Madrid/ESA Spain XMM

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