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KIDS: mapping the universe with weak lensing Konrad Kuijken, Leiden

KIDS: mapping the universe with weak lensing Konrad Kuijken, Leiden . VISTA 4m telescope 0.6 sq.deg. IR camera 16 2kx2k detectors 0.35” pixels. VST 2.6m telescope 1 sq.deg. optical camera (OmegaCAM) 32 2kx4k detectors 0.21” pixels. 60 b=45 30.

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KIDS: mapping the universe with weak lensing Konrad Kuijken, Leiden

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  1. KIDS: mapping the universe with weak lensingKonrad Kuijken, Leiden

  2. VISTA 4m telescope 0.6 sq.deg. IR camera 16 2kx2k detectors 0.35” pixels VST 2.6m telescope 1 sq.deg. optical camera (OmegaCAM) 32 2kx4k detectors 0.21” pixels

  3. 60 b=45 30 -75 b=-60 1500 sq.deg. in ugriZYJHK +2000 sq.deg. in i (+UKIDSS YJHK)

  4. KIDS vs. SDSS, CFHTLS (M.Neeser)

  5. KIDS: Kilo-Degree Survey • ESO Public Survey • 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 searches

  6. 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

  7. ‘w’ (weak lensing) • Weak lensing constraints • Lensing effect depends on relative distances of source and lens:  Dls/Ds • 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!

  8. ‘w’ (wiggles) (P. Schuecker) • 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)

  9. Effect of w • Angular diameter distances changes • Lensing measures • Baryon oscillations measure dA(z)

  10. Effect of w

  11. Photo-z from KIDS/UKIDSS (Saglia) r<23.5 r<24r<25 0<z<6 0<z<1.5 Scatter further reduced with deeper IR data

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

  13. Data Flow (E. Valentijn) • Spread over 6 data centers in Europe • Astro-WISE system = federated database + query-driven pipeline processing • Db-wide control of calibration and quality ctl. • Mini-VO with a mini-GRID • Integration with UKIDSS / VISTA IR data • Data delivery will be to ESO

  14. Multi-band photometry • Accurate colours for photo-z: need PSF and aperture matching • Classically: reconvolve all images to common (worst?) seeing, then perform aperture photometry on all • New approach: compute all fluxes for a small set of standard PSFs and apertures • Can do this catalogue-based, eg via shapelets • Match surveys with diff’t pixel scales, etc.

  15. KIDS: the kilo-degree survey • About 8 TB of reduced image pixels • 40TB of raw data • 440 nights of observing time • VO-like work plan (federated database environment Astro-WISE) • ‘Natural’ survey speed for VST / OmegaCAM, and VISTA • Fits nicely between SDSS/UKIDSS-LAS and CFHTLS-WIDE: • SDSS: • deeper (2 mag), narrower (5x) • finer image quality (2x) • cf. CFHLS: • wider (9x), shallower (1 mag) • comparable/better(?) image quality • Includes near-IR  stellar mass; photo-z’s; highest redshifts; … • Spectra from 2dFGRS & SDSS  know the foreground structure

  16. 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

  17. Lensing / photo-z survey • VST/OmegaCAM: 1 sq deg, 2.6m telescope • VISTA/VISTACAM: 0.6 sqdeg, 4m telescope • 1500 sq.deg. of ugri (~400n VST) + ZYJHK (~200n VISTA) • Deeper in r, with good seeing • VST 2m deeper than SDSS (1m shallower than CFHTLS) • VISTA 1.5m deeper than UKIDSS

  18. KIDS(Leiden, Groningen, Munchen, Bonn, Paris, Naples, Imperial, Edinburgh, Cambridge) 60 b=45 30 • Overlaps: • UKIDSS • SDSS • 2dFGRS • CFHLS • COSMOS • AA • 780 sq deg. CFHLS 2dFGRS SDSS/UKIDSS LAS

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

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