The Apache Point Observatory Galactic Evolution Experiment (APOGEE)

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The Apache Point Observatory Galactic Evolution
Experiment (APOGEE)
Ricardo Schiavon1 (for the team)
1 Gemini Observatory
Construction and Evolution of the
Galaxy Princeton, Feb 27, 2009
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SDSS-III
http//www.sdss3.org
APOGEE 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-a
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 stars
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APOGEE People

• APOGEE Leadership S. Majewski (PI, UVa)
• M. Skrutskie (Instrument Scientist, UVa)
• J. Wilson (Deputy Instrument Scientist, UVa)
• R. Schiavon (Survey Scientist, Gemini
  Observatory)
• C. Allende-Prieto (Abundances and Stellar
  Parameters Task Leader, Mullard)
• M. Shetrone (Spectral Reduction Task Leader,
  HET)
• J. Johnson (Field/Target Selection Task Leader,
  Ohio State)
• P. Frinchaboy (Field/Calibration Task Leader,
  U.Wisc., NSF Fellow)
• D. Bizyaev (Radial Velocities Task Leader, APO)
• I. Ivans (Princeton), J. Holtzman (NMSU)
• Significant Contributors to Date K. Cunha, V.
  Smith (NOAO), R. OConnell (Uva), Neil Reid
  (STScI),
• R. Barkhouser, S. Smee (JHU), J. Gunn
  (Princeton), T. Beers (Michigan State)
• C. Henderson, B. Blank (Pulseray Machine
  Design), D. Spergel (Princeton)
• G. Fitzgerald, T. Stolberg (NEOS), T. OBrien
  (OSU), E. Young (UofA)
• J. Crane (OCIW), S. Brunner, J. Leisenring (Uva)

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APOGEE
Context it seems like we live in a ?-CDM
Universe gt Does the Milky Way fit in that
picture?
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APOGEE at a glance

• Bright time 2011 to 2014
• 300 fiber, R 24,000, cryogenic spectrograph
• H-band 1.51-1.68?
• Typical S/N 100/pixel _at_ H12.5 for 3-hr
  integration
• Typical RV uncertainty lt 0.5 km/s
• 0.1 dex precision abundances for 15 chemical
  elements
• 105 2MASS-selected giant stars probing all
  Galactic populations

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Advantages of a High Res. H-band Survey

• Red giants/red clump are bright in NIR.
• Complete point source sky catalogue to H gt 14
  available from 2MASS, augmented by GLIMPSE and
• UKIDSS where available.
• No need for new photometry!

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Advantages of a High Res. H-band Survey
AV 1 boundary

• AH / AV 0.17 ? ?2 flux for AV 1 ?100
  flux for AH 1
• Access to dust-obscured galaxy
• Precise velocities and abundances for giant
  stars across the Galactic plane, bar, bulge,
  halo gt HOMOGENEITY
• Low atmospheric extinction makes bulge
  accessible from North
• Avoids thermal background problems of longer l

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APOGEE Depth
Solar metallicity RGB tip star int (hr)
Hlim AV d(kpc) 3 12.5 5
27 10 13.4 10 27
Fe/H -1.5 RGB tip star int (hr) Hlim
AV d(kpc) 3 12.5 0 40
10 13.4 0 60
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APOGEE in Context
Deeper at high Av than everybody else
Gal.Cen.
AV
5
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APOGEE Spectrograph

• The APOGEE Dewar will be housed in the basement
  of the support building about 40 meters from the
  base of the telescope.
• The red line approximates the main fiber run. A
  plug on the cartridge end will insert into a
  fiber coupling receptacle on the cartridge.
• Slit head is cryogenic and permanently housed in
  the instrument.

2.5-meter
cartridge
coupler
APOGEE
SDSS-III Sloan Review - APOGEE
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394 mm
Blanche et al 2004
VPH mosaic grating (265 x 450 mm illuminated)
Refractive Camera (Si Fused Silica)
300 fiber pseudo-slit embedded in fold mirror
Three HAWAII-2RG arrays (NIRCam-style detector
mount)?
1.7 m
Fiber feedthroughs
2.1 m
LN2 cooled Dewar
Collimator
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Science Goals

• 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 SFR and IMF of bulge/disk as function
  of radius, metallicity/age, chemical evolution
  of inner Galaxy.
• Determine nature 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
• Find Pop III stars

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Science Goals

• 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 SFR and IMF of bulge/disk as function
  of radius, metallicity/age, chemical evolution
  of inner Galaxy.
• Determine nature 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
• Find Pop III stars?

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Top Level Science Requirements
Reliable statistics (level of solar
neighborhood) in many (R, q, Z) zones

• APOGEE seeks to construct similar figures for
  many elements and for many other discrete
  Galactic zones.
• e.g., GCE models predict variations in these
  distributions and in radial X/H gradients
  differing at few 0.01 dex level per radial bin
• for gradients requires 0.01 dex in ltX/Hgt
  or gt100 stars with 0.1 dex per radial bin
• for X/H-Fe/H distributions requires (100
  stars)(20 Fe/H bins)(dozens of zones)
  105 stars

Venn et al. (2004) 781 compiled stars
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Orders of Magnitude

• order of magnitude leaps
• 1-2 orders more high S/N, high R spectra
  ever taken
• 3 orders larger than any other high R GCE
  survey
• 3 orders more high S/N, high R near-IR spectra
  than ever taken
• First week of observations will exceed all
  previous work!

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High-Res. Abundances in H-band

• Numerous lines of molecular CN, OH, CO to give
  LTE-based CNO abundances (most abundant metals in
  universe)
• Plenty of clean lines of Fe, a-elements (O, Mg,
  Si, S, Ca, Ti, Cr), Fe peak (V, Mn, Ni), and some
  odd-Z (e.g., Na, K, Al)

Simulated APOGEE spectra
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Simple Ideas

• APOGEE will make possible straightforward tests
  of Galaxy formation scenarios by verifying how
  relevant quantities vary with time.

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Simple Ideas

• Dias et al. (2003) catalogue of open clusters

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Simple Ideas
Various elemental abundances in open clusters
Yong et al. 2005
Age
RGC
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Simple Ideas

• APOGEE targets will be seen at large distances
  even at very large extinction
• 1 of APOGEE sample, 5 stars/cluster, 200
  clusters!

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Galactic Bulge

• We know star formation in the center, old stars
  (e.g. Baade window), presence of a bar, high
  metallicity (Rich 88), probably an abundance
  gradient (Zoccali et al. 2007), mostly
  alpha-enhanced (Fullbright et al.).
• Which fraction of the bulge stellar mass was
  formed in situ, which fraction from mergers,
  which fraction from secular evolution driven by
  bar instabilities (e.g., Norman et al. 1996)?

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Galactic Bulge

• Kobayashi (2004) CDM-based 124 SPH simulations
  of elliptical galaxies, including radiative
  cooling, star formation, SN and wind feedback,
  chemical enrichment
• Solid symbols are monolithic collapse, open
  symbols are systems with a lot of previous
  merging
• The more merging, the shallower the abundance
  gradients

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Spectrum Synthesis
Arcturus
Synthesis
Ti
Mg
Mg
Mg
Allende Prieto
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Anticipated Deliverables

• ?-calibrated, sky-subtracted,
  telluric absorption-corrected, 1-D spectra
• RVs to 0.5 km/s external accuracy
• log(g), Fe/H, Teff (making use of 2MASS
  colors)
• elemental abundances to within 0.1 dex accuracy
• for 15 elements, including CNO, other ?,
  Fe-peak, Al, K)

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SDSS-III High-level Schedule
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APOGEE Timeline

• Conceptual Design review completed April 16, 2008
• Long lead-time items (detectors, materials for
  large optics) to be procured immediately
  following PDR (with review board's permission).
• Operations begin roughly 2 years following
  early-2009 critical design review.

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Institutional Members

• Signed MOUs.
• Univ. of Arizona
• Cambridge Univ.
• Case Western Univ.
• Univ. of Florida
• German Participation Group (AIP, MPE, MPIA, ZAH)
• Johns Hopkins Univ.
• Korean Institute for Advanced Study
• Max Planck Astroph., Garching
• New Mexico St. Univ.
• New York Univ.
• Ohio State Univ.
• Univ. of Pittsburgh
• Univ. of Portsmouth

• Princeton Univ.
• UC Santa Cruz
• Univ. of Utah
• Univ. of Washington
• Vanderbilt
• Univ. Virginia
• MSU/ND/JINA
• Brazilian PG (ON and four Univ.)
• Near-term possibilities
• Fermilab
• French PG (APC, IAP, CEA,)
• UC Irvine
• LBNL
• Penn State Univ.
• Spanish PG (three CSIC units)
• Univ. of Tokyo/IPMU
• Other institutions and individuals are in
  discussions.

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What We Want to Talk to You About

• Theorists we need you to produce models for us
  to rule out.
• All the survey is being defined. If I were
  you, I would get involved now. Bring your ideas.
  Lets discuss.

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Spectrum Synthesis
Meléndez et al. (2003)
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Red H-band Window
Must have element Important to have/very
desirable element Nice to have element (also
not shown Cr, Co)
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Blue H-band Window
Must have element Important to have/very
desirable element Nice to have element (also
not shown Cr, Co)
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The Promise of Detailed Chemical Abundance Studies
Star Formation Rate and (possibly) timescale
McWilliam 1997

• ? elements primarily formed in Type II SNe
• Type Ia start to contribute gt1 Gyr
• Direct indicator of early star formation rate
  (SFR)

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The Promise of Detailed Abundance Analysis
Thick disk shows O enhancement gt faster/more
efficient enrichment than halo
Disk Halo
Thick disk (Bensby et al.)

Situation for the bulge is unclear gt much more
and better data needed
K giants (Cunha Smith 2006)
M giants (Origlia Rich 2005)
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The Promise of Detailed Chemical Abundance Studies
The Initial Mass Function
(MgTi) / Fe
(SiCa) / Fe

• Relative abundances of different a elements
  reflects mass of SN progenitors Probes IMF
• (e.g., McWilliam Rich 1997 differences in a
  elements for bulge --- on right, above)

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Top Level Science Requirements

• First large scale, systematic, uniform
  spectroscopic study of all Galactic stellar
  populations to understand
• chemical evolution at precision, multi-element
  level (especially preferred, most common metals
  CNO) -- sensitivity to SFR, IMF
• tightly constrain GCE and dynamical models
  (bulge, disk, halo)
• access to normally ignored, dust-obscured
  populations
• Galactic dynamics/substructure with very precise
  velocities

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Top Level Science Requirements

• search for rare populations of stars (e.g., Pop
  III in bulge)

• E.g., state of the art bulge MDFs photometrically
  (shaded) and spectroscopically (open)
• high res numbers not much more nowadays (several
  dozen)
• APOGEE seeks to construct statistically
  significant bulge MDFs for many elements
• If Population III (e.g., Fe/H lt -4) exists in
  the bulge, clearly very rare and requires 10,000s
  of stars to find.
• If there is dynamical substructure in inner
  Galaxy, also need large samples to see
  granularity (Freeman et al. argue for 106 stars
  to get dozens of representatives from each
  accreted body)

110 stars, R lt 4800
322 stars, R 3000
12 stars, R 17,000
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Galaxy Evolution Models and Current Data
Radial Metallicity Gradients

• GCE models (lines) poorly constrained by current
  meager data (points)(and notice poor model match
  to radial gradient of only one element)

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Dynamics

• Disk/Rotation Curve
• Surveys of stellar disk dynamics outside solar
  vicinity typically lt 100 stars
• HI tangent point analyses assume circular
  rotation, insensitive to non-axisymmetric
  effects (e.g., arms) and inoperable outside
  solar circle V(gtRsun) poorly known.
• Limited info on MW mass profile, Tully-Fisher
  position.
• Galactic Bar
• Little current data, but possibly wide-ranging
  influence
• Radial motions affect gas-mixing, metallicity
  gradients.
• Bar alignment puts streaming motions mostly in
  RVs.
• Bulge
• Connection of velocities and chemistry provide
  strong constraints on inflow of material into
  bulge, influence of bar
• Halo
• Internal dynamics of substructure

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The Sagittarius Dwarf
The Sagittarius Dwarf
In the mid-nineties, a dwarf galaxy was found to
be falling on the Milky Way Galaxy.
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Dynamics

• Disk/Rotation Curve
• Surveys of stellar disk dynamics outside solar
  vicinity typically lt 100 stars
• HI tangent point analyses assume circular
  rotation, insensitive to non-axisymmetric
  effects (e.g., arms) and inoperable outside
  solar circle V(gtRsun) poorly known.
• Limited info on MW mass profile, Tully-Fisher
  position.
• Galactic Bar
• Little current data, but possibly wide-ranging
  influence
• Radial motions affect gas-mixing, metallicity
  gradients.
• Bar alignment puts streaming motions mostly in
  RVs.
• Bulge
• Connection of velocities and chemistry provide
  strong constraints on inflow of material into
  bulge, influence of bar
• Halo
• Internal dynamics of substructure

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Structure in the Halo
Vivas Zinn (2006)
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Resolution/Sampling
Baseline spectrograph focal plane characteristics
Lambda (nm) Sampling Resolution
1536.4 2.3 20,000
1601.1 2.56 20,842
1626.0 2.69 21,166
1680.5 3.09 21,875
Blue window
Red window
Wavelength coverage includes 2 tolerance for
magnification error and room for RV slop
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APOGEE Instrument Overview
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APOGEE Physical Layout

• The APOGEE dewar will be housed in the basement
  of the support building about 30 meters from
  the base of the telescope.
• The red line approximates the main fiber run. A
  plug on the cartridge end will insert into a
  fiber coupling receptacle on the cartridge.
• Approximately 10km of bulk fiber will be needed
  for the main line.

2.5-meter
cartridge
coupler
APOGEE
45
People

• APOGEE Leadership S. Majewski (PI, UVa)
• M. Skrutskie (Instrument Scientist, UVa)
• J. Wilson (Deputy Instrument Scientist, UVa)
• R. Schiavon (Survey Scientist, Gemini
  Observatory)
• P. Frinchaboy (Targeting Coordination Team,
  U.Wisc., NSF Fellow)
• R. OConnell (Steering Committee, UVa)
• Significant Contributors to Date K. Cunha, V.
  Smith (NOAO), M. Shetrone (Texas), J. Holtzman
  (NMSU), R. Barkhouser (JHU), J. Gunn
  (Princeton), C. Henderson, B. Blank (Pulseray
  Machine Design), C. Allende-Prieto (London),
  D. Bizyaev, F. Leger (APO), R. Indebetouw, M.
  Nelson, R. Patterson, R. Rood, J. Hawley (UVa)
• Other Contributors
• J. Bullock (UCI), J. Crane, A. McWilliam (OCIW),
  D. Geisler (Concepcion), K. Johnston
  (Columbia),
• J. Munn (USNOFS), I.N. Reid (STScI), D. Spergel
  (Princeton), M. Weinberg (UMass), S. Hawley (U.
  Washington)

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Spectrum Synthesis
Meléndez et al. (2003)
Schiavon et al. (1997)
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APOGEE

• One of four SDSS-III surveys
• A large, high-resolution, NIR, spectroscopic
  survey of stars in the Galaxy