Integral Field Spectroscopy

• 2D spectroscopic coverage, generally done with either lenslets, or fiber bundles

• Galaxy science
  • Velocity fields, stellar and gas: maps of mean velocity, velocity dispersion, higher order moments. Implications for mass derivations, galaxy 3D shapes, formation mechanisms (population of orbits), mergers, interactions, etc. Global scaling relations. Velocity functions.
  • Stellar population characteristics and variations across galaxy: absorption line indices, full spectral decompositions
  • Gas properties and variations across galaxy: emission line ratios, diagnostic diagrams, etc. Star formation rates, shocks, etc.
  • ``Aperture corrections'' to central measurements (e.g., SDSS)

• Instruments
  • Many
  • Many cover only small fields ($<\sim 10$ arcsec)
  • SAURON on WHT
  • PPAK on Calar Alto 3.5m

• Techniques
  • Work with 3D image cubes
  • Issue: crosstalk between locations, depending on seeing, etc.
  • Issue: sky subtraction
  • Issue: data visualization
  • IFS wiki

Previous surveys

SAURON

• Project home page
• Used SAURON spectrograph (33"x41") on WHT
• ``Representative sample" (in ellipticity and absolute magnitude) of 72 early-type galaxies
• Many publications: kinematics, populations, etc.

ATLAS3D

• Project home page
• Uses SAURON spectrograph (33"x41")
• Complete sample of 260 early type galaxies within local (42 Mpc) volume,selected on basis of K band luminosity

CALIFA

• Project home page
• $\sim$ 600 galaxies using PPAK ($\sim 100$ to date?), full range of Hubble types
• Sample in color-magnitude space
• Visualizing some data: see paper

MaNGA (Mapping Nearby Galaxies at APO)

• Wiki page
• Builds on SDSS
  • Uses existing BOSS spectrographs (perhaps modified to include even more fibers)
  • Extends SDSS single fiber measurements to full galaxy
• $\sim$ 15 fiber bundles in SDSS 3 degree field
• Sample: $\sim$ 10000 galaxies
  • Selection from SDSS sample by stellar mass (details TBD)
  • Primary (``Main") sample: reach target S/N$\sim$ 5 per pixel at 1.5 $r_e$
  • Secondary (``Large'') sample: to $2.5 r_e$, predominantly for emission lines
  • test sample

• Technical issues
  • Making fiber bundles: 19, 37, 61, 91, 127 fibers. Packing fibers. Stripping fibers
  • Dithering. Note issues with differential refraction!
  • Sky subtraction: sky variation, number of fibers
  • Spectrophotometry: fat fibers vs fiber bundles vs dithering with normal fibers

Other surveys

• CALIFA
• SAMI: AAT. Smaller field, different environments? southern hemisphere