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Surveys with OmegaCAM / VST KIDS Koen Kuijken, Leiden

Surveys with OmegaCAM / VST KIDS Koen Kuijken, Leiden. KIDS: Kilo-Degree Survey. ESO public survey proposal Accepted as core survey (May) 1700 square degrees ~ 400 nights Sloan band survey, median redshift 0.8 Goals: Halo structure (weak lensing)

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Surveys with OmegaCAM / VST KIDS Koen Kuijken, Leiden

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  1. Surveys with OmegaCAM / VSTKIDSKoen Kuijken, Leiden

  2. KIDS: Kilo-Degree Survey • ESO public survey proposal • Accepted as core survey (May) • 1700 square degrees • ~ 400 nights • Sloan band survey, median redshift 0.8 • Goals: • Halo structure (weak lensing) • Dark energy (w via ang. power spec; wk lensing) • Galaxy evolution vs. environment • Cluster searches • Higher-redshift quasars than SDSS • White dwarf samples

  3. KIDS(Leiden, Groningen, Munchen, Bonn, Paris, Naples, Imperial, Edinburgh, Cambridge) • Overlaps: • UKIDSS • SDSS • 2dFGRS • CFHLS • COSMOS • 960 sq deg. CFHLS SDSS DR2 2dFGRS

  4. KIDS(Leiden, Groningen, Munchen, Bonn, Paris, Naples, Imperial, Edinburgh, Cambridge) • Overlaps: • 2dFGRS • VISTA! • 720 sq deg. • Perfect for VLT and AAT, APEX, ALMA 2dFGRS

  5. Post-PSP field layout

  6. Integration times, sensitivities Optimize for weak lensing • Use all moon phases, best 80% of seeing VISTA Wide-i

  7. KIDS vs. SDSS

  8. Galaxy-galaxy lensing 45 sq. deg from RCS survey (Hoekstra, Yee, Gladders 2004) Galaxy-mass correlation Halo radii Halo shapes KIDS: 7x smaller errors (#pairs) Good photo-z’s (b/g), spectroscopic z’s (lenses) Study effect by galaxy type

  9. ‘w’ (weak lensing) • Weak lensing constraints • Lensing effect depends on relative distances of source and lens • Measure lensing strength as function of redshift • Deduce distance as function of redshift • Geometrical test of expansion history: w (5%) • Needs well-controlled photo-z’s!

  10. ‘w’ (wiggles) • Use scale of power spectrum wiggles as standard candle • Spec redshift surveys: need few 100,000 gals for detection • Photometric redshift surveys: wash out z information, but many more galaxies! • KIDS: 67,000,000 gals with r<23.5 (20- fluxes) • Photo-z accurate to 0.03(1+z) (ugrizYJHK) • w(z=0) to <15% from KIDS • w(z=1) to better accuracy z=0.6 z=1.0z=1.4 Angular waveno. (deg-1)

  11. Photo-z from KIDS/UKIDSS r<23.5 r<24r<25 0<z<6 0<z<1.5

  12. Typical SED’s (r~24, redshift~1) • KIDS ugriz • UKIDS YJHK

  13. z>6.4 QSOs • Combine with IR (UKIDSS, VISTA) • Look for IR objects faint in i or z • Find brown dwarfs and high-z QSOs • Expect ~7 @ z>6.4 • Many fainter z~5-6

  14. The challenges • Distributed dataprocessing (ASTRO-WISE!) • Work in a KIDS context • Central monitoring of calibration • Quality control is the key: • Some overlaps between teams  intercompare • Version control of the procedures, parameters, etc. • Advanced QC tools, incl lensing and photo-z • Integration with ‘static’ IR surveys (VISTA, UKIDSS) • Image and catalogue level

  15. The challenges II • Lensing measurements with shapelets • Photo-z : matched-PSF and matched-aperture photometry for colors • Shapelets session at 3pm.

  16. SUMMARY • 1700 sq.deg.: • Equatorial strip = UKIDSS / 2dFGRS area • South Galactic Pole = 2dFGRS field VISTA!! • 5-band u’g’r’i’z’ • Integration time 2hrs per field  440 nts • Use range of seeing conditions, moon phase • Optimized for weak lensing survey • Other applications: large-scale structure, cluster evolution, galaxy evolution, …

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