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

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

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

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

Stars at the solar neighbourhood

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

2df kinematic survey stars from a disrupted satellite galaxy ?

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)

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

Age-Metallicity-Kinematics at the solar neighborhood Edvardsson et al 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

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

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

Performance of survey telescope Telescope Aperture Field of View A* F Gemini Gemini WHT WHT VLT VLT SDSS/SEGUE SDSS/SEGUE df/AAOmega df/AAOmega df/RAVE df/RAVE LAMOST

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.

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

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

SEGUE imaging and spectroscopic observing plan

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

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

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

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

GAIA – ESA only mission

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

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

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,

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,

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 20 th magnitude or so, and in that way be complementary to a project such as GAIA which will get spectra for only brighter objects”,

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