Stellar population Studies with Stellar population Studies with LAMOSTLAMOST
- - Chen BingChen Bing - - ContentsContents
• Galactic structure & EvolutionGalactic structure & Evolution
• Related ProjectsRelated Projects (SDSS/SUGUE, RAVE, AAOmage, GAIA)(SDSS/SUGUE, RAVE, AAOmage, GAIA)
• Collaboration & ProposalCollaboration & Proposal
Galactic structureGalactic structureThin DiskThin Disk color-magnitude diagram Hipparcos; Density law Double exponential color-magnitude diagram Hipparcos; Density law Double exponential Scale length/Scale height 2250/350 pcScale length/Scale height 2250/350 pc Age=(0,10 Gyr), Fe/H =(0.01, -0.37 dex), d[Fe/H]/dR=-0.07 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(SigmaU, sigmaV, sigmaW) up to (43, 27, 17) km/s, Vad up to 15 km/sThick DiskThick 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 pcScale length/scale height 3500/750 pc Age=11 Gyr, Fe/H = -0.78, d[Fe/H]/dR=0Age=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/sHaloHalo 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=0Age= 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 streamsStellar streams,, Dark matterDark matter
Stellar populations in the GalaxyStellar 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
Ages of Galactic disk and halo 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. 1998
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 neighbourhoodStars at the solar neighbourhood
2df kinematic survey2df kinematic survey--The Anglo Australian Old stellar population SurveyThe 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 2df kinematic survey stars from a disrupted satellite galaxy ? stars from a disrupted satellite galaxy ?
Halo stream around the Milky wayHalo stream around the Milky way
The peculiar main-sequenceat a a distance of 11 kpc from the Sun in the direction of (l,b)=200,20)
Halo stream around the Milky wayHalo 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 neighborhoodAge-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
Local dark matterLocal dark matterCreze 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
The Thick disk – Halo InterfaceThe Thick disk – Halo Interface
2df metallicities vs radial velocity
Performance of survey Performance of survey telescopetelescope
Telescope Aperture Field of View ATelescope Aperture Field of View A** F F Gemini 8.1 0.17 1.8Gemini 8.1 0.17 1.8 WHT 4.2 0.5 4.4WHT 4.2 0.5 4.4 VLT 8.1 0.4 10VLT 8.1 0.4 10 SDSS/SEGUE 2.4 2.5 36SDSS/SEGUE 2.4 2.5 36 2df/AAOmega 3.9 2.0 612df/AAOmega 3.9 2.0 61 6df/RAVE 1.2 6.6 656df/RAVE 1.2 6.6 65LAMOST 4.0 5.0 400LAMOST 4.0 5.0 400
SDSS Multi-object SDSS Multi-object SpectrographsSpectrographs
End-to-end system throughput, including the telescope
The two SDSS spectrographs. The squareBlack openings accept the fiber opticsSlitheads, 320 fibers each.
SDSS Multi-object SDSS Multi-object SpectrographsSpectrographs
Number of spectrographs 2 Number of spectrographs 2 Spectral resolution 1800Spectral resolution 1800
Blue Channel range 3900-6000 Blue Channel range 3900-6000 A A Red Channel range 6000-9100 Red Channel range 6000-9100 A
Fiber inputs per spectrograph 320Fiber inputs per spectrograph 320 Telescope aperture 2.5 mTelescope aperture 2.5 m
Fiber diameter 180 microns ( 3” ) Fiber diameter 180 microns ( 3” )
SDSS science plate targetsSDSS science plate targets ~ 500 galaxies, 100 QSO, and 30 stars~ 500 galaxies, 100 QSO, and 30 stars SDSS key projectSDSS key project redshifts for 10^6 galaxies and 10^5 quasarsredshifts for 10^6 galaxies and 10^5 quasars
SEGUESEGUE(Sloan Extension for Galactic underpinnings and (Sloan Extension for Galactic underpinnings and
Evolution)Evolution)The proposed Observing StrategyThe proposed Observing Strategy
• imaging ~ 3500 square degrees mostly at |b| < 30imaging ~ 3500 square degrees mostly at |b| < 30• The spectroscopic targets from SDSS & SEGUEThe spectroscopic targets from SDSS & SEGUE 170 well-selected sky directions170 well-selected sky directions Two plates in each field, one normal exposure plate, and one double-length plate to a limit of Two plates in each field, one normal exposure plate, and one double-length plate to a limit of
g=20.3g=20.3
SEGUE imaging and SEGUE imaging and spectroscopic observing spectroscopic observing
planplan
Allocation of fibers per plate Allocation of fibers per plate pair pair
• 25 White dwarfs25 White dwarfs• 175 Blue Horizontal Branch, F-turnoff stars175 Blue Horizontal Branch, F-turnoff stars• 375 G dwarfs375 G dwarfs• 200 K giant200 K giant• 200 Low-metallicity candidates200 Low-metallicity candidates• 175 M and K dwarfs175 M and K dwarfs• 130 sky fibers and calibration standards130 sky fibers and calibration standards To an accuracy To an accuracy RVs TRVs Teff log g [Fe/H]eff log g [Fe/H] 7 km/s 100-150 K 0.3-0.5 dex 0.25-0.3 dex7 km/s 100-150 K 0.3-0.5 dex 0.25-0.3 dex
RAVERAVE(Radial Velocity Experiment)(Radial Velocity Experiment)
Using the 1.2-m UK Schmidt telescope of the Using the 1.2-m UK Schmidt telescope of the AAOAAO, ,
Observing strategy (Observing strategy (use of the Ca-triplet at 8400-use of the Ca-triplet at 8400-8750, RVs better than 2 km/s)8750, RVs better than 2 km/s)
• Pilot survey (2003-2005) bright-time at the 6df Pilot survey (2003-2005) bright-time at the 6df using the existing 150-fibre 6df system, 7” diameterusing the existing 150-fibre 6df system, 7” diameter• Main Survey (2006-2010)Main Survey (2006-2010) will use the proposed 2250 fibre systemwill use the proposed 2250 fibre system 50 million stars, magnitude limited (V=16), all sky 50 million stars, magnitude limited (V=16), all sky
surveysurvey looking for a northern counterpartlooking for a northern counterpart
AAOmega AAOmega A 3.9 m telescope providing a general purpose spectroscopic A 3.9 m telescope providing a general purpose spectroscopic
facilityfacility
AAOmega – multiple-object modeAAOmega – multiple-object mode• Field of view 2 degreesField of view 2 degrees• Number of fibres 350-392 Number of fibres 350-392 • Angular size of fibre 2”Angular size of fibre 2”• Wavelength range 3700 –9500 AWavelength range 3700 –9500 A• Peak system throughput (Blue/Red) 0.17/0.20Peak system throughput (Blue/Red) 0.17/0.20• Spectrl resolution 1300 – 8000Spectrl resolution 1300 – 8000• Spectral resolution 3.5 ASpectral resolution 3.5 A• Limiting mag B=22.0Limiting mag B=22.0
AAOmega Galaxy Science AAOmega Galaxy Science Still under investigation, proposal Still under investigation, proposal
includingincluding• Large AAOmega + RAVE stellar population surveyLarge AAOmega + RAVE stellar population survey• Halo structures, Thick disk metallicity – kinematicsHalo structures, Thick disk metallicity – kinematics• DM distributionDM distribution
Input Catalogues exist (2MASS, …)Input Catalogues exist (2MASS, …)
Complement SEGUE, LAMOST in the north ..Complement SEGUE, LAMOST in the north ..
GAIA – ESA only missionGAIA – ESA only mission
GAIA GAIA • Astrometry (V < 20)Astrometry (V < 20)• Radial velocity ( V < 16-17)Radial velocity ( V < 16-17) Third component of space motionThird component of space motion• Photometry ( V < 20) Photometry ( V < 20)
A Complete survey, launch date 2010-A Complete survey, launch date 2010-2012,2012,
+ 5 year observations, final catalog ~ + 5 year observations, final catalog ~ 20182018
DIVADIVA German national Space science missionGerman national Space science mission
• Magnitude limited all-sky surveys (V =15-16), Magnitude limited all-sky surveys (V =15-16), a mission between Hipparcos & GAIA a mission between Hipparcos & GAIA
• DIVA and RAVE complement each other. DIVA and RAVE complement each other. permit to determine the full 6-D distributionpermit to determine the full 6-D distribution• CANCELLEDCANCELLED !! !! unable to close the funding gap of ~ 15 million EUROunable to close the funding gap of ~ 15 million EURO• A big loss for RAVE, and its scienceA big loss for RAVE, and its science
Collaboration & ProposalCollaboration & ProposalSpectroscopic 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 ProposalOne 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)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”
,
My traces abroadMy traces abroad
•1989-1993, Ph.D, SIMBAD/CDS, France1989-1993, Ph.D, SIMBAD/CDS, France multi-color star count survey multi-color star count survey
•1994-1999, Postdoc, Barcelona Spain1994-1999, Postdoc, Barcelona Spain Hipparcos & GAIAHipparcos & GAIA•1999-2001, SDSS, Johns Hopkins USA1999-2001, SDSS, Johns Hopkins USA SDSSSDSS •2001-now, XMM Madrid/ESA Spain2001-now, XMM Madrid/ESA Spain XMMXMM
Top Related