Surveys with OmegaCAM / VST KIDS Koen Kuijken, Leiden

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Surveys with OmegaCAM / VSTKIDSKoen Kuijken,
Leiden
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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

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KIDS(Leiden, Groningen, Munchen, Bonn, Paris,
Naples, Imperial, Edinburgh, Cambridge)
CFHLS
SDSS DR2
2dFGRS

• Overlaps
• UKIDSS
• SDSS
• 2dFGRS
• CFHLS
• COSMOS
• 960 sq deg.

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KIDS(Leiden, Groningen, Munchen, Bonn, Paris,
Naples, Imperial, Edinburgh, Cambridge)
2dFGRS

• Overlaps
• 2dFGRS
• VISTA!
• 720 sq deg.
• Perfect for VLT and AAT, APEX, ALMA

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Post-PSP field layout
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Integration times, sensitivities

• Use all moon phases, best 80 of seeing

filter Exp time (s) Medn seeing () 5-? 2 AB
u 900 1.0 24.8
g 900 0.75 25.4
r 1800 0.6 25.2
i 1080 0.75 24.2
z 2520 0.75 23.2
TOT 7200
lt0.7 (40) 0.7-0.85 (20) 0.85-1.1 (20)
Dark (50) r g u
Grey (15) i i i
Bright (35) z z z
VISTA
Wide-i
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KIDS vs. SDSS
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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-zs
(b/g), spectroscopic zs (lenses) Study effect by
galaxy type
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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-zs!

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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 rlt23.5 (20-? fluxes)
• Photo-z accurate to 0.03(1z) (ugrizYJHK)
• w(z0) to lt15 from KIDS
• w(z1) to better accuracy

z0.6 z1.0 z1.4
Angular waveno. (deg-1)
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Photo-z from KIDS/UKIDSS
rlt23.5 rlt24 rlt25
0ltzlt6 0ltzlt1.5
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Typical SEDs (r24, redshift1)

• KIDS ugriz
• UKIDS YJHK

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zgt6.4 QSOs

• Combine with IR (UKIDSS, VISTA)
• Look for IR objects faint in i or z
• Find brown dwarfs and high-z QSOs
• Expect 7 _at_ zgt6.4
• Many fainter z5-6

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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

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The challenges II

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

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SUMMARY

• 1700 sq.deg.
• Equatorial strip UKIDSS / 2dFGRS area
• South Galactic Pole 2dFGRS field VISTA!!
• 5-band ugriz
• 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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Shears from shapelets