1. 3D dark matter map z=0.5 z=0.7 z=1 z=0.3 Right ascension Declination z=0 Mapping dark matter with weak gravitational lensing Richard Massey CalTech

2. Weak lensing results from the HST COSMOS survey Richard Massey (CalTech ) with Jason Rhodes (JPL), Joel Berg é (Saclay), Richard Ellis (CalTech), Alexis Finoguenov (Garching), Luigi Guzzo (INAF), Catherine Heymans (UBC), J-P Kneib (Marseilles), Alexie Leauthaud (Marseilles), Alexandre Refregier (Saclay), Nick Scoville (CalTech), James Taylor (Waterloo), Ludovic Van Waerbeke (UBC) and the worldwide COSMOS team of 70+ scientists Mapping dark matter with weak gravitational lensing

3. z observer =0 z galaxy ≈1 z lens ≈0.3–0.5 Observe light from distant galaxies, behind any structure we’re interested in. Gravitational Lensing Translation Magnification Shear Flexion/curvature Gravitational lenses are sensitive to any mass along the line of sight and, like glass lenses, are most effective when it is half way between the source and the observer.

4. NASA, ESA, and M. J. Jee (JHU) CL 0024+17

5. Shapes of galaxies are random so, in the absence of lensing, averaging ~100 would produce a circle. Galaxies on adjacent lines of sight are coherently distorted. z observer =0 z galaxy ≈1 z lens ≈0.3–0.5 Observe light from distant galaxies, behind any structure we’re interested in. Weak Gravitational Lensing Gravitational lenses are sensitive to any mass along the line of sight and, like glass lenses, are most effective when it is half way between the source and the observer. Translation Magnification Shear Flexion/curvature

6. 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) Hubble Space Telescope COSMOS survey Gravitational lensing convergence  projected mass

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

8. Redshift tomography z=0.3 z=0.5 z=0.7 years ago

9. 3D dark matter map z=0.5 z=0.7 z=1 z=0.3 Right ascension Declination NASA, ESA and R. Massey (California Institute of Technology) z=0

10. 3D dark matter map animation ESA/Hubble (M. Kornmesser & L. L. Christensen)

11. Statistical analysis of 3D mass distribution R. Massey et al. (ApJ 2007), J. Lesgourgues et al. (JCAP submitted) z=0.7 Shear-shear correlation function z=0.5 z=0.3 Cosmological parameter constraints WMAP SDSS Ly  forest COSMOS 3D weak lensing VHS Ly  forest

12. Redshift-distance relation James Taylor et al. (in prep) Cumulative shear signal Redshift Cumulative shear signal Redshift Cumulative shear signal Redshift Well-know shape as a function of angular diameter distance from simple lens geometry

13. Distribution of visible and dark matter

14. 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)

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

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

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

18. “Bullet” cluster 1E0657-56 1.5’ Doug Clowe, Marusa Bradac et al. (Astrophysical Journal 2006)

19. The largest particle accelerator in the universe

20. “Bullet” cluster 1E0657-56 1.5’ Doug Clowe, Marusa Bradac et al. (Astrophysical Journal 2006)

21. Radial mass profile Face-on bullet James Jee et al. (Astrophysical Journal 2007)) Two clusters along line of sight

22. Face-on bullet NASA, ESA and M. J. Jee (Johns Hopkins University)

23. Conclusions & future prospects Remarkably fast progress since first statistical detections of cosmic shear in 2000. Gravitational lensing is now a major tool in cosmology. We can now compare the large-scale distribution of baryons to that of mass. In general, baryonic structures are built inside a dark matter scaffold. Discrepancies on small scales reveal the different (e.g. non-interacting) properties of dark matter. Statistical analyses of the mass distribution constrain cosmological parameters, trace the growth of structure, and measure the expansion history of the universe. Could not have been done from the ground. Wide-field imaging from space is essential, backed up by multicolour photometry: the untimely failure of ACS is heartbreaking. Hubble provides a unique proof of concept for ambitious, dedicated missions in the future.

24. Fin

25. Lensing sensitivity with redshift Resolved background galaxies Redshift Foreground lensing sensitivity

26. Can anything be done from the ground?

27. Ground vs space (mass maps) Using 71 galaxies per arcmin 2 SPACE GROUND R. Massey et al. (Nature 2007), M. Kasliwal et al. (Proc. AAS 2007)

28. Ground vs space (B-mode/noise in mass maps) R. Massey et al. (Nature 2007), M. Kasliwal et al. (Proc. AAS 2007) SPACE GROUND Using 71 galaxies per arcmin 2

29. Ground vs space (cluster detection over z range) M. Kasliwal et al. (Proc. AAS 2007) SPACE GROUND SPACE GROUND Redshift 0.73Redshift 0.93 Redshift 0.22Redshift 0.35 SPACE GROUND SPACE GROUND

30. Mass vs x-rays A. Finoguenov (in prep)

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

32. Effect of CTE trailing on the mass map

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

34. PSF variation J. Rhodes (ApJ 2007)

35. Manufacture realistic images, containing a known shear signal. Animations show 0-10% shear in 1% steps (real signal is ~2%). Real image Simulated image R. Massey et al. (MNRAS 2004) Shear TEsting Programme (STEP) simulations

36. Shear TEsting Programme (STEP) results C. Heymans et al. (MNRAS 2006) R. Massey et al. (MNRAS 2007)

37. Mass vs light 2D projection R. Massey (Nature 2007) 20’

38. Growth of dark matter structure R. Massey et al. (ApJ 2007) Fraction of mass on various scales

39. Radial mass profile of cluster CL 0024+17

40. PSCz galaxy density < 150 Mpc/h W. Sutherland et al. (1991) COSMOS mass density, R. Massey et al. (Nature 2007) Lensing is coming of age