1. KIDS: mapping the universe with weak lensing Konrad 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) SDSSCFHTLS 6 x area1/9th area 2 mag shallower 1 mag deeper 2x worse seeing ~same

5. 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 KIDS: Kilo-Degree Survey

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:  D ls /D s –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) 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=1.0 z=1.4 Angular waveno. (deg -1 ) (P. Schuecker)

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

10. Effect of w

11. Photo-z from KIDS/UKIDSS r<23.5 r<24 r<250<z<6 0<z<1.5 Scatter further reduced with deeper IR data (Saglia)

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

13. Data Flow 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 (E. Valentijn)

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

17. 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

18. 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 <0.7” (40%) 0.7- 0.85” (20%) 0.85- 1.1” (20%) Dark (50%)r’g’u’ Grey (15%)i’ Bright (35%)z’ filterExp time (s) Medn seeing (“) 5-  2” AB u’9001.024.8 g’9000.7525.4 r’18000.625.2 i’10800.7524.2 z’25200.7523.2 filterExp (s) 5-  2” AB cf. UKIDSS Z50023.1- Y40022.4+1.6 J40022.2+1.8 H30021.6+1.6 K50021.3+1.3

19. 60 b=45 30 Overlaps: –UKIDSS –SDSS –2dFGRS –CFHLS –COSMOS –AA  780 sq deg. 2dFGRS SDSS/UKIDSS LAS CFHLS KIDS (Leiden, Groningen, Munchen, Bonn, Paris, Naples, Imperial, Edinburgh, Cambridge)

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