1. Cosmic scaffolding and the growth of structure Richard Massey (CalTech ) with Jason Rhodes (JPL), David Bacon (Edinburgh), Joel Berg é (Saclay), Richard Ellis (CalTech), Alexis Finoguenov (Garching), Catherine Heymans (UBC), J-P Kneib (Marseilles), Alexie Leauthaud (Marseilles), Alexandre Refregier (Saclay), Nick Scoville (CalTech), Elisabetta Semboloni (Bonn), James Taylor (Waterloo), Ludovic Van Waerbeke (UBC) and the 70+ COSMOS team Cosmic scaffolding and the growth of structure

2. Core HST data in COSMOS field http://irsa.ipac.caltech.edu/Missions/cosmos.html Largest ever HST survey 577 contiguous ACS pointings 1.6 square degrees in I F814W band (V SDSS at z=1) Depth I F814W <26.6 (at 5  ) 2 million galaxies ~80 resolved galaxies/arcmin 2 N. Scoville et al. (ApJ 2007)

3. Multicolour data in COSMOS field P. Capak et al. (ApJ 2007), B. Mobasher et al. (ApJ 2007)  z/(1+z)= 0.05, 0.15

4. Lensing sensitivity with redshift Resolved background galaxies Redshift Foreground lensing sensitivity 1/r 2

5. Weak lensing analysis Convergence  projected mass Real data (no Bhuvnesh here!) RRG shear measurement Calibrated on STEP3-like sims PSF model varies with focus Parametric CTE correction

6. Multiscale wavelet reconstruction method J.-L. Starck, S. Pires & A. Refregier (A&A 2006)

7. B-mode check for residual systematics R. Massey et al. (Nature 2007)

8. Comparison with baryons Weak lensing mass contours (HST) Extended x-ray emission (XMM-Newton) Galaxy number density (Subaru/CFHT) Galaxy stellar mass (Subaru/CFHT) R. Massey et al. (Nature 2007)

9. Dealing with photometric redshift degeneracies P. Capak et al. (ApJ 2007), B. Mobasher et al. (ApJ 2007) Faint galaxies X X photo-z 0123401234 probability

10. z=0.3 z=0.5 z=0.7 Redshift tomography (palaeocosmology)

11. Mass vs light tomography (z~0.3) ~19Mpc  19Mpc R. Massey et al. (Nature 2007)

12. Mass vs light tomography (z~0.5) ~26Mpc  26Mpc R. Massey et al. (Nature 2007)

13. Mass vs light tomography (z~0.7) ~31Mpc  31Mpc R. Massey et al. (Nature 2007)

14. z=0.5 z=0.7 z=1 z=0.3 Right ascension Declination z=0 Bacon & Taylor 3D reconstruction

15. 3D dark matter map animation ESA/Hubble (M. Kornmesser & L. L. Christensen)

16. 3D cosmic shear z=0.7 Shear-shear correlation function  + (  ) z=0.5 z=0.3 R. Massey et al. (Astrophysical Journal 2007)

17. Full 3D analysis Traditional 2D analysis Cosmological parameter constraints R. Massey et al. (Astrophysical Journal 2007)

18. Growth of structure R. Massey et al. (Astrophysical Journal 2007) Fraction of mass on different scales

19. Conclusions Largest ever HST survey - ideal proof of concept for future, dedicated missions in space. Various problems encountered, but all HST-specific and none generic to space. Know what needs to be done better! Comparison of the large-scale distribution of baryons to that of mass, which could not have been done from the ground. In general, mass traces light - consistent with a scenario where baryonic structures are built inside a preformed dark matter scaffold. Discrepancies on small scales reveal the different nature of dark matter. Statistical analysis of the mass distribution constrains cosmological parameters, traces the growth of structure (and measures the expansion history of the universe). Multicolour follow-up, particularly in near IR, is essential! 3D analysis yields ~3x improvement.

20. Fin

21. PSF variation HST’s thermal “breathing” affects both size and ellipticity of PSF Effective focus changes by 3  m per orbit 12  m in ~days J. Rhodes (ApJ 2007), J. Jee (ApJ 2005)

22. PSF variation J. Rhodes (ApJ 2007)

23. Charge Transfer (in)Efficiency STIS image, courtesy Paul Bristow Trailing during CCD readout creates a spurious, coherent ellipticity. Affects photometry, astrometry and morphology of faint galaxies. CCD readout register

24. Effect of CTE trailing on the mass map

25. Largest ever survey with HST 1.6 square degrees in I F814W band Depth I F814W <26.6 (at 5  ) 2 million galaxies, z median =1.2 Small, diffraction-limited PSF ~80 resolved galaxies/arcmin 2 Follow-up from radio to x-rays Photo-zs from 17 optical/IR bands Dark matter simulation at z=0.5 Andrey Kravtsov and Anatoly Klypin (National Center for Supercomputer Applications) Compare to simulations Gravitational lensing convergence  projected mass

26. Lensing sensitivity with redshift Resolved background galaxies Redshift Foreground lensing sensitivity 1/r 2