Download - SDSS-III Science
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SDSS-III Science
Myungshin Im (SNU)
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Scientific Themes
• Dark energy and cosmological parameters (BOSS)
• The structure, dynamics, and chemical evolution of the Milky Way (SEGUE-2, APOGEE)
• The architecture of planetary systems (MARVELS)
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SDSS-III Projects (2008-2014)
• BOSS (Baryon Oscillation Spectroscopic Survey)
• SEGUE-II (Sloan Extension for Galactic Understanding and Exploration)
• APOGEE (The APO Galactic Evolution Experiment)
• MARVELS (Multi-object APO Radial Velocity Exoplanet Large-area Survey)
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BOSS – Dark Energy and the Geometry of Space
• Precision cosmology with baryon acoustic oscillation. • Measure the eq. of state parameters (w=P/rho) at high a
ccuracy (+-0.08), using..,• 1.5 million luminous red galaxies (LRGs) out to z ~ 0.7 (I
< 20 AB mag; vs 18.5 current) over 10,000 sq. degree.• Lyman-alpha forest spectra of 160,000 QSOs at 2.2 < z
< 4.• 1,000-fiber spectrograph (7 deg2,resolution R ~ 2000, im
proved CCD efficiency (vs 640 fibers)• Wavelength: 360-1000 nm• Fall 2009 – Spring 2014
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BOSS - Baryon Acoustic Oscillation• Imprint of the acoustic phenomena caused by the coupling of the photo
n and gas perturbations in the early-universe (< 0.4 Myr). • The physical scale is well-understood, thus can be used as a standard
ruler.• It shows up as an enhanced overdensity with a characteristic scale of
~ 150 Mpc.
(From D. Eisenstein) (www.sdss3.org)
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BOSS – BAO constraints on cosmological parameters
• P=w ρ
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BOSS Science Topics• Precision cosmology: Eq. of state parameter (and its z-evolution), test of general r
elativity, Hubble constant (1% accuracy).• Galaxy-galaxy lensing: LRG-mass cross correlation (dark matter halo profile,dark
matter auto-correlation function).• Large-scale structure: 7 x increase over SDSS-II (k < 0.2 Mpc-1).• Evolution of red, massive galaxies: stellar population, fundamental plane, dark
matter halo study, number density and luminosity function, environment – provides an important pivot point to study the higher redshift population
• Galaxy lensing by LRGs: mass profile of early-types (e.g., SLACS: Bolton et al. 2006).
• QSO survey: study of the fainter QSOs at the peak of QSO activity (z=2.5) such as LF, clustering, AGN feedback.
• High-z QSOs: High redshift QSO survey (z = 3.6 – 6.0 QSOs, x2).
z=0.245
z=0.08
2.2”
New grav. Lens (Im et al. 2008, in prep.)E/S0s at z < 1(Im et al. 2002)
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SEGUE-2• Imaging + Spectroscopic survey of galactic structures.• 250,000 stars to g=19 mag.• Measure abundances and metallicity of stars (0.3 dex in [Fe/H]), and radial
velocity (4 km/sec).• Discover merger remnants and explore the history of the Galactic evolution.• Also, study the galactic structure in conjunction with APOGEE and MARVLES.
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SEGUE-2 • 1. Dark time during fall 2008 – spring 2009• 250,000 stars to g=19 mag• R-2000, S/N=25 spectra• Velocity error 4 km/sec, [Fe/H] error 0.3 dex.• 2. Bright time parallel program, 2010-2014, additional 100,000 stars to g=17 mag.• Mainly at b > 20 or < -20.
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SEGUE Science Topics
• Galactic Stellar Populations: explore the physical connection among objects in the galactic structure (for disks, bulges, use APOGEE).
• Hierarchical Formation of the Galaxy: search of the residue of the merger process via velocity substructure and chemical finger printing determine the contribution of accretion history in the inner galaxy.
• Population III: discovery of Pop-III stars and study of the nucleosynthetic products of Pop-III stars.
• Halo Substructure: identification of halo substructures such as Monoceros ring (Newberg et al. 2002) mass of the disrupted parent satellite and limits on dynamical heating of streams in the dark halo.
• Chemo-dynamics of Halos: mapping of the velocity fields and abundance distribution of stars over large area (+ age) help understand the formation of the galactic halo.
• Legacy Survey of Star Clusters: large, systematic spectroscopic exploration globular and open clusters.
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APOGEE• Systematic survey of > 105 (giant) stars in the Galactic disk and bulg
e (high extinction).• 1.52 – 1.69 micron (H-band), H < 13.5 mag (2MASS-selected), vel_
err ~ 0.5 km/sec at S/N ~ 100 and R ~ 20,000 (vs. S/N ~ 25, R ~ 2,000 of SEGUE).
• Measure abundances of > 15 elements, and precise radial velocities.
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APOGEE – Galactic Chemodynamics• Bright time observations, spring 2011 – 2014• Understand the chemical enrichment process as a function of time and loca
tion out to 75 kpc.• 1.52 – 1.69 micron (H-band) – OH, CN, CO (C, N, O from Type-II SN); alpha-
elements (O, Mg, Si, S, Ca, Ti) from Massive stars (IMF constraint), iron peak elements (Cr, V, Mn, Fe, Co, Ni) from Type-Ia SNe; odd-Z elements (Na, K, and Al) from SN II.
• Precise radial velocity measurement (0.5 km/sec) dynamics of the galactic disk/bulge (e.g., rotation curve of the outer disk with spectroscopic parallax), isolation of dynamically distinct population of star clumps (merger remnants + chemical fingerprinting)
Keck H-band spectra of two globular cluster giants (Origlia et al. 2005) APOGEE will give 0.1 dex accuracy in [X/Fe]
[Fe/H]=-0.60 [Fe/H]=-0.17
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APOGEE Science Topics
• Galactic Stellar Populations: explore the physical connection between the bulge, thin disk, thick disk, and halo populations through chemical, dynamical information.
• Hierarchical Formation of the Inner Galaxy: search of the residue of the merger process via velocity substructure and chemical finger printing determine the contribution of accretion history in the inner galaxy.
• Population III: discovery of Pop-III stars and study of the nucleosynthetic products of Pop-III stars.
• Halo Substructure: identification of halo substructures such as Monoceros ring (Newberg et al. 2002) at low-b mass of the disrupted parent satellite and limits on dynamical heating of streams in the dark halo.
• Galactic Dynamics: determine large scale dynamics of the Milky Way with spectroscopic parallaxes and the radial velocity measurements rotation curve to the outermost reaches of the disk (MW follows TF-relation? Flynn et al. 2006).
• The Galactic Bulge: mapping of the velocity fields and abundance distribution of bulge stars over large area (+ age) help understand the formation of the galactic bulge.
• The Galactic Bar: provides insight on the little known dynamics and chemistry of the galactic bar.
• Legacy Survey of Low-Latitude Star Clusters: largest systematic spectroscopic exploration of low-b globular and open clusters.
• Star Formation: constrain the shape of the IMF (α and odd-Z elements). • Interstellar Extinction: map the 3-D distribution of Galactic dust and constrain variation
s in the interstellar extinction law (with other wavelength data).
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MARVLES• Massive search of short-to-intermediate period giant
planets around a large, well-characterized stars.• Radial velocity monitoring of 10,000 MS stars and 1,000
giants.• Test theoretical models of the formation, migration,
dynamical evolution of giant planet systems.
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MARVELS• Bright time observations, fall 2008 – spring 2014• Two 60-fiber interferometric spectrographs (DFDI, dispersed fixed-delay interf
erometer: proto-type used at KPNO 0.9m/2.1m, and also at Keck).• 10,000 main sequence stars, 1,000 giant stars, V = 8 – 12 mag.• 25-35 observations per star over 18 months• Velocity error: 12 m/sec at V=10 mag• Mass sensitivity at P=100 days: 0.35 M_jup (V=9.5), 0.7 M_Jup (V=11.5).• ~ 150 short-to-intermediate M > 0.2 M_jup stars (P < 1000 days)
(From Ge, 2002)
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MARVEL Science• Test of the models of planet formation, migration, and dynamical evolution:
physics of planet migration through compilation of large number of M > M_Jup planets.
• Planets with large eccentricities: eccentricities/period data will constrain leading models.
• Multiple planet systems: MARVLE planets can be monitored for detecting longer period, lower mass companions.
• Host star properties: the correlation of planetary systems with metallicity, mass, age etc can be explored (e.g., Ida & Lin 2004; Santos et al. 2004).
• Planet transit study: ~ 10 transit system with follow-up obs. Unbiased sample.
• Rare classes of planetary systems: hot Juipters, rapidly interacting multiple planet systems, very-hot Jupiters, planets with extremely high exccentricities.
• Brown dwarf desert: Apparent paucity of 15 – 80 Mjup companions can be studied.
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Organization
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Data Release Plan
• Similar to the previous SDSSs
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SDSS-III for Korean Astronmers
• Many things to do from cosmology, extragalactic astronomy, galactic astronomy (near-field cosmology), and exo-planet study.
• We need to explore science topics and make the maximal use of this extraordinary dataset.