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LAMOST .vs. Dark matter and Dark energy

LAMOST .vs. Dark matter and Dark energy. 大天区面积多目标光纤光谱天文望远镜 The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). Location Xinglong Station, National Astronomical Observatories, Chinese Academy of Sciences Cost RMB 235 Million yuan (~$30M) Construction Period 7 years.

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LAMOST .vs. Dark matter and Dark energy

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  1. LAMOST.vs.Dark matter andDark energy

  2. 大天区面积多目标光纤光谱天文望远镜The Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST)

  3. Location Xinglong Station, National Astronomical Observatories, Chinese Academy of Sciences • Cost RMB 235 Million yuan (~$30M) • Construction Period 7 years

  4. Project Organization Xinglong Station, NAOC the site Beijing: NAOC Project HQ Instruments & Software Science Nanjing: NIAOT (NAOC) Telescope Instruments Hefei: USTC Science

  5. Basic parameters of LAMOST • 4-meter Schmidt telescope • The declination of observable sky area ranges from -10 to +90. • 20 square degree of the FOV • 4000 fibers • Spectrum resolution: VPH (Volume Phase Holographic) Grating R=1000, 2000, 5000, 10000

  6. Key Projects • Extra-galactic spectroscopic survey — Galaxy and QSO redshift survey • Stellar spectroscopic survey — Structure of the Galaxy, and so on. • Cross identification of multi-waveband survey.

  7. LAMOST will make possible a wide range of scientific projects • a wide-field, multi-object, high-precision instrument on a 4m telescope can concentrate on large-scale (tens to hundreds of thousands of objects) scientific projects which can’t be carried out on 8-m telescopes, or in ‘single object’ mode on 4m telescopes.

  8. Strategies of galaxy redshift survey • Magnitude limited (B=20.5) sample Intrinsic faint object with mean z=0.2 • Luminous Red Galaxy (LRG) Deep: 0.3 < z < 0.8

  9. Redshift survey of Galaxy Low Resolution spectroscopy: • To obtain the spectra of faint celestial objects (Galaxy and AGN) down to 20.5m with 1nm spectral resolution in 1.5 hours exposure. • Wavelength range: 370—900 nm • Dark night

  10. SDSS Collaboration 2002 LOCAL REDSHIFT SURVEY After 2dF and SDSS • Make big local leaps in surveysize/volume

  11. Redshift distribution of LAMOST galaxies survey

  12. LRG sample Advantage to select LRG • Red color → easy to find the candidate • Most luminous galaxy → Map large cosmological volume • Correlated with cluster → To detect and study the clustering

  13. The SDSS colour selection of LRGs is very efficient, so it could be make an large cosmological volume sample with high completeness and reliability.. • Complementing to SDSS LRGs sample up to r < 20.5, to get galaxy redshift sample with 0.38 < z < 0.8 . • Overlap in redshift space between Galaxy and QSOs

  14. Scientifically, there is a great benefit in having the two new surveys (Galaxy and QSDs) co-extensive since there is now a substantial overlap in redshift space, providing opportunities to compare the clustering and environments of the two classes of object.

  15. QSO survey • Combine the high quality digital image data of SDSS (5 colors) with powerful spectroscopic capabilities of LAMOST to conduct a deep wide field spectroscopic suevey for Quasars

  16. Dark matter and Dark Energy • 95% of the mass-energy is dark • The “Dark Universe” takes at least two Form: Dark Matter Dark Energy

  17. Two simulations of strong lensing by a massive cluster of galaxies: the same amount of mass is more smoothly distributed over the cluster, causing a very different distortion pattern.

  18. Two simulations of strong lensing by a massive cluster of galaxies. dark matter is clumped around individual cluster galaxies (orange), causing a particular distortion of the background galaxies (white and blue).

  19. Combine the high quality image of the lensing galaxy with powerful spectroscopy capabilities of LAMOST to conduct a deep wide-field spectroscopic sample of all these galaxies, it will be very helpful for the test of the distribution of Dark matter

  20. Distribution of Galaxies • Luminosity function of galaxies, • Galaxy clustering depend the subset of galaxies: color, luminosity, type,… • The redshift-space distortion of the large-scale clustering • Topology of Large Scale Structure

  21. Astrophysical challenge for the dark energy • Since the dark energy will effect on the expansion of the universe, the dark energy affects all observations of astronomical objects at large redshift

  22. Dark energy and Cosmological test • Geometrical features of a universe with a cosmological constant • Accelerating universe • Angular diameter distance • Luminosity distance • The redshift-angular size and redshift-magnitude relations • Galaxy counts

  23. Dark energy has the following defining properties: • (1) it emits no light; • (2) it has large, negative pressure • (3) it is approximately homogeneous (more precisely, does not cluster significantly with matter on scales at least as large as clusters of galaxies). • Because its pressure is comparable in magnitude to its energy density, it is more “energy-like” than “matter-like” (matter being characterized by p<<ρ ). • Dark energy is qualitatively very difierent from dark matter.

  24. Dark energy and Cosmological test • Age of the universe • The gravitational lensing rate • Dynamics and the mean mass density • The baryon mass fraction in clusters of galaxies • The cluster mass function • Biasing and the development of nonlinear mass density fluctuations • The mass autocorrelation function and nonbaryonic matter

  25. The growth of matter density perturbations

  26. Cosmological parameters from SDSS and WMAP

  27. Dark energy measurements

  28. Baryon oscillations • provide a standard rod for mapping the evolution of the geometry of the universe with redshift • measure the equation of state of the dark energy

  29. Effect of the survey window function

  30. BARYON ACOUSTIC PEAK IN THE LARGE SCALE CORRELATION FUNCTION OF GALAXIES

  31. Galactic Structure and Evolution

  32. It is evident that our own Milky Way galaxy is the only galaxy that we can presently study at sufficiently high spatial (and kinematical) resolution, and at sufficient depth, to address many of the open questions on the physics of galaxy formation

  33. Stellar spectroscopy plays a crucial role in the study of our Galaxy, not only providing a key component of the 6-dimensional phase space of stellar positions and velocities, but also providing much-needed information on the chemical composition of individual stars. Taken together, information on space motion and composition can be used to unravel the formation process of the Galaxy.

  34. Galactic Structure LAMOST will be able to detect and characterise stars in all of the major components of the Galaxy down to a magnitude limit of V~18 at low spectral resolution R=1000 or Middle spectral resolution for bright stars R=6000 - 12000

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