APOGEE Apache Point Observatory Galactic Evolution Experiment
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APOGEE Apache Point ObservatoryGalactic Evolution ExperimentMatthew Shetrone
SDSS-IIIAPOGEE: an infrared, high resolution spectroscopic survey of the stellar populations of the Galaxy
BOSS: will measure the cosmic distance scale via clustering in the large-scale galaxy distribution and the Lyman- forest
SEGUE-2: will map the structure, kinematics, and chemical evolution of the outer Milky Way disk and halo
MARVELS: will probe the population of giant planets via radial velocity monitoring of 11,000 starshttp://www.sdss3.org
APOGEE at a glance Bright time SDSS-III survey, 2011.Q2 to 2014.Q2 300 fiber, R 22,500, cryogenic spectrograph, 7 deg2 FOV H-band: 1510 1690 nm (AH /AV ~ 1/6) Typical S/N = 100/pixel @ H=12.2 for 3-hr integration RV uncertainty < 100 m/s in 1hr 0.1 dex precision abundances for 15 chemical elements (including C, N, O, Fe, other , odd-Z, possibly neutron-capture) 105 2MASS-selected [(J-K) > 0.5] predominantly giant stars, probing all Galactic populations
Unblended Lines in H band?Molecules are very prevalent in the H-band: CO, CN, OH in addition to the atomic features: Mg, Fe
The Spectra A small piece of the APOGEE specta for stars near the tip of the giant branch in several GC.
OH is visible even in the most metal-poor clusters but the double metal molecules disapear quickly with decreasing metallicity.
A 3-D chemical abundance distribution (many elements), MDFs across Galactic disk, bar, bulge, halo. Probe correlations between chemistry and kinematics (note Gaia proper motions eventually as well). Constrain SFH and IMF of bulge/disk as function of radius, metallicity/age, chemical evolution of inner Galaxy. Detailed study of Galactic bar and spiral arms and their influence on abundances/kinematics of disk/bulge stars. Measure Galactic rotation curve (include spec. p., Gaia pm) Search for and probe chemistry/kinematics of (low-latitude) halo substructure (e.g., Monoceros Ring). Combine with existing/expected optical, NIR and MIR data and map Galactic dust distribution using spec. ps, constrain variations in extinction law Look for early generations of stars and/or their signatures in the chemistry of the most metal-poor bulge starsBroad Science Goals
*Current Field PlanField Center Plan:24 hour12 hour3 hour (science)3 hour (calibration)1 hour~343 fields ~600 star clusters~116,000 science stars including Kepler fields
Ongoing Effort Some half dozen technical papers in progress. Several science papers in progress, some published DR10: First APOGEE data release (summer 2013). All Year 1 (May 2011-July 2012) data Targeting & suppl. data (e.g., photometry, proper motions, cat. source) Extracted, calibrated 1-D spectra RVs, RV variability, v sin i Teff, log g, , [Fe/H], [/Fe], C, NDR12: Last APOGEE I data release (December 2014) All APOGEE 1 (May 2011 July 2014) dataStellar parameters and velocities as in DR10Individual elemental abundances (Si, Ca, Al, V, etc..)
Early Science Highlights Stellar ages from the APOKASC (Epstein/Pinnsoneault et al.) To date, ~2800 Kepler stars (mostly asteroseismology giants) observed by APOGEE. APOKASC?
Early Science HighlightsSeem to be a family of stars on leading edge of bar. Detection of high velocity stars in Galactic bulge/bar (Nidever/Zasowski et al. 2012) If this interpretation is correct, a negative RV counterpart should befound in the IV quadrant
Early Science Highlights Metallicity gradients in the disk (Holtzman/Hayden et al.) Distances from ASPCAP + RJCE dereddenings.
Early Science Highlights Improving knowledge about open clusters (Frinchaboy et al.)
Early Science Highlights Be stars found among telluric standards (Chojnowski et al.) Brackett Line Emission
Your Free AccessBasic Searches: There are two basic ways to make a search for APOGEE results: 1) From the SDSS-III DR10 Catalog Archive Server (CAS or SkyServer) http://skyserver.sdss3.org/dr10/en/home.aspx or 2) From the DR10 Science Archive Server (SAS) http://dr10.sdss3.org/basicIRSpectra. The SAS is what you might use if you want the actual spectra, while the SkyServer is useful for making lists of targets or data results. Below we show how one might search for targets in a cluster and then retrieve a spectrum of a cluster star:CAS SkyServer Example Queryhttp://skyserver.sdss3.org/dr10/en/tools/search/IRQS.aspx*
Observing the Central Milky Way with APOGEE+Sloan 2.5-mFrom Apache Point Observatory:Galactic center culmination @ altitude = 28 (airmass = 2.1!)Sky above 2 airmasses: Apache Point Observatory Las Campanas Observatory
Extending APOGEESDSS3/APOGEE Survey ends July 2014SDSS3: Resulting 105 sample very large, but still scratching surface: Halo sample relatively shallow. Chance to go deep. Bulge currently relatively meagerly sampled (~8,000 stars). Bulge, bar and inner disk hard to do from APO!! high airmass reduces FOV due to differential refraction effects only partial bulge coverage pile-up of inner Galaxy longitudes over small range of RAAPOGEE extension for After Sloan-III: APOGEE-2North significantly increase sample by factor of several.Instrument ready from the start ideally another ~250,000 stars.APOGEE-2South, cloned instrument on Du Pont 2.5-m at LCO100,000 170,000 stars.
Science of an APOGEE-2North Significantly increase halo, thick disk outer disk samples. Substantially boost overall statistics, observing from Day 1. Opportunity for increasing time series work. stellar and substellar companions leveraging RV precision. both 1-m dark time & 2.5-m bright time operations continue. Expand extremely useful synergy with Kepler mission. 10 visits per tile. increase asteroseismology sample. characterize planet/non-planet hosts. robustly assess Kepler false alarm rate. dynamical masses from eclipsing binaries. continue contributing to fundamental astrophysics.
Science of an APOGEE-2South Large chemical and kinematical study of the Galactic bulge 65,000-100,000 stars (or more) & ~15 elements Significantly increase sampling of low end of MDF.Increase chance of seeing first stars (Tumlinson 2010) ...or constrain their nature from abundance imprint on succeeding generations (Eckstroem et al. 08).X-shaped bulge (McWilliam & Zoccali 2010, De Propris et al. 2011).Star formation, clusters & history of Galactic center environment.Sample other rare stellar types. (e.g., C-stars, CN-strong stars, S-type, Mira, very young stars)Center of halo and disk distributions.Explore dynamics of the bar(s). Fulbright et al. 2007: The notion of a bulge that formed early, and rapidly, remains attractive. This conclusion is consistent with observations of galaxy formation at high redshift. However, it remains vital to study additional elements and larger samples of stars because the fossil record locked in the bulge's composition has the potential to provide a detailed record of its history that is unmatched by anything that can be inferred from the observations of distant galaxies."
Science of an APOGEE-2SouthSignificant/homogeneous surveys of 4 other Local Group galaxies:Large and Small Magellanic Clouds, Sagittarius, Centauri Halo/disk substructure and (as)symmetriesDisk/bar/spiral arm symmetry by inclusion of III and IV quadrants.Clear views of Monoceros/Canis Major/Argo (warp or tidal stream?).Disk warp and disk edge/truncation.Far side of the disk, beyond bulge.Follow-up for southern hemisphere photometric surveys (VVV and SkyMapper). Star cluster chemistry (85% lie below celestial equator)Metal-rich bulge/disk clusters study (not possible in north).Important targets: e.g., 47 Tuc, NGC 288/362, N6338/N6441, NGC 6528, 6533, Sgr & Magellanic clusters.Integrated light in Magellanic clusters.
APOGEE-2 Sky CoverageApproaching half million stars in combined APOGEE-1 & -2.
A picture from APOKASC showing how we get very preliminary ages. I have taken the 1127 Kepler stars that have already been observed by APOGEE and run through the ASPCAP pipeline. Using preliminary seismic parameters (from Daniel Huber), I found the seismic mass and logg for these stars (gray points). Adding in APOGEE's [Fe/H] information allows us to compare to isochrones (Yonsei-Yale isochrones shown in this figure) to get age.
For some stars, we have more detailed seismic information which allows us to determine its evolutionary state (from Dennis Stello). These are indicated by the colored points. So you can see where RC stars, secondary RC, and first ascent RGB stars live. There are already 42 confirmed first ascent RGB stars (gold stars) in the sample, and we will be able to get good ages for those (do not have to worry about the effect of mass loss).Comparison to various Galactic models suggests that these high RVs arebest explained by stars in orbits of the Galactic bar potential, although some observational featuresremain unexplained.Watch out for this: 600 clusters will be targeted in the end of the survey.Tumlinson: in the bulge, only about ~10% of all [Fe/H] < -3 stars were formed at z > 15. Tumlinson: in the bulge, only about ~10% of all [Fe/H] < -3 stars were formed at z > 15.