1. Center for Theoretical Physics University of Provence Marseille Christian Marinoni Testing Cosmological Models with High Redshift Galaxies

2. Gravity Field equations Metric RW line element Nature of Dark Energy ? New source ? New gravitational physics ? Inhomogeneus universe

3. Testing Gravity at z=1 - with 2 nd order statistics : - redshift evolution of the linear growth factor of density fluctuations - with 3 rd order statistics : - Redshift Evolution of the skewness of the galaxy density fluctuations Testing cosmological models - The cosmological lensing of galaxy diameters Outline

4. δ Field 2DFGRS/SDSS stop here Marinoni et al. 2008 A&A in press (arXiv 0802.1838) Gaussian Filter R=2Mpc)

5. 2dFGRS (Colless et al. 00) =0.1 120,000 galaxies f=0.5±0.1 σ=390±50 km/s (Peacock et al. 2001, Nature) Testing gravity with second order statistics : VVDS LeFevre et al. 05 =0.75 ~6,000 galaxies f=0.9±0.4 σ=400±50 km/s (Guzzo et al. 2008 Nature 2008)

6. Constraining the physics behind acceleration In principle, f can reveal the physical origin of the acceleration Predicted constraints from SPACE missison In linear theory

7. Testing gravity with third order statistics : Skewness Galaxy fluctuations were significantly non Gaussian even at early times Conclusion: 3 rd order GIP predictions consistent with data only if, even locally, biasing is non-linear at the level measured by VVDS See also Feldman et al. 2001 Biasing at high z cannot be described in terms of a single constant Marinoni et al. 2005, A&A, 442, 801 R=10h -1 Mpc Marinoni et al. 2008 A&A in press (arXiv:0802.1838) Verde et al. 01 Croton et al. 2005 Juszkievicz et al. 1993 Hivon et al. 1995 Mass skewness Galaxy skewness

8. D Angular Diameter Test Metric constraints using the kinematics of high redshift disc galaxies Marinoni, Saintonge, Giovanelli et al. 2007 A&A, 478, 41 Saintonge, Master, Marinoni et al. 2007 A&A, 478, 57 Marinoni, Saintonge Contini et al. 2007 A&A, 478, 71 Theory predicts : Standard Rod Selection Saintonge et al. 2008 A&A,478, 57 Observationally Confirmed

9. The angular diameter test with high-velocity rotators Predictions for V>200km/s (big) galaxies zCOSMOS (1 deg 2 ): ~ 1300 rotators and (σ D /D) int =20% full VVDS (16 deg 2 ): ~ 20 000 rotators and (σ D /D) int =20%

10. Many cosmological tests make use of only two functions of redshift The angular diameter distance d A (z) and the radial comoving distance r(z) Violation of consistency might indicate Non-RW geometry Tests of the Cosmological Principle These two quantities are not independent, as they are related by the cosmic consistency relation (e.g. Stebbins 2007) where Spatial curvature

11. The consistency tests with high velocity rotators ~30 disc galaxies hosting a supernovae in the zCOSMOS field Sinfoni + HST VIMOS+ Cosmos

12. Z=0.5 Z=0.9 Implementation Strategy: HST/Cosmos imaging survey: HR Spectroscopy (VIMOS) VLT HST Observations underway with VIMOS at VLT in the COSMOS field (accepted ESO proposal, P.I. L. Tresse) Very Quick (…but large) Survey!! ~1300 rotators down to Iab 22.5 in only 30h Retarget in High spectroscopic resolution zCOSMOS discs with known emission lines and redshift

13. Preliminary data Comparison with the predicted angular evolution in the standard ΛCDM background 0<v(km/s)<100 100<v(km/s)<200 Standard Rod Selection Best fitting model ΛCDM

14. Cosmological Constraints from Preliminary data By imposing that luminosity emitted per unit mass was higher in the past we can exclude : * SCDM (EdS) at 3σ * OCDM (Ω M =Ω T =0.3) at more than 1σ with 30 rotators at =1 only !!! Observational constraints: 1)luminosity emitted per unit mass was higher In the past. 2)SB evolution as inferred from data Which is the region of the cosmological parameter space which is compatible with these external constraints?

15. Conclusions - semi-linear GIP predictions for skewness evolution are consistent with data in the range 0<z<1.5 only if biasing is non-linear at the level measured by VVDS. If local (z=0) bias is linear  GIP ruled out at 5 sigma! -Evolution of the linear growth factor gives insigths into the nature of DE. Still large errorbars affects VVDS measurements. Need larger deep surveys (e.g. SPACE) - Observations underway in the COSMOS/HST field to collect a large sample of velocity selected standard rods (VIMOS @ VLT) and test cosmology with the angular diameter test of cosmology

16. EVOLUTION EVOLUTION According to theory (analytic models and simulations) big baryonic discs already completed their evolution before z=1 Chiappini, Matteucci & Gratton 1997 Boissier & Prantzos 2001 Bowens & Silk 2001 Ferguson & Clarke 2003 Somerville et al. 2007 Theory predicts that the rotation velocity at a given stellar mass is only about 10% larger at z~1 than at the present day Excluded Region `matter density Test’

17. Suppose there is a mild evolution ? Does evolution bias results? z 1/2 z z2z2 DE equation of state parameterization

18. Structural Parameters Evolution 0<V(km/s)<100 100<V(km/s)<200

19. Study how bounded regions in the evolution parameter space map into the cosmological parameter space. 2 nd Strategy : (we are unlucky…. evolution is substantial) Mapping between cosmological parameter space and evolution space Fiducial model : cosmological parameters : Ω M =0.3,Ω Q =0.7,w=-1 Evolution parameters : -δ=(D(z=1.5)-D(0)/D(0))=0.26 (smaller disk in the past) -ΔM=M(z)-M(0)= -1.4 (brighter galaxies in the past) 2 possibilities : * Extract cosmology once the amount of disc/luminosity evolution is known at some given redshift. * Extract evolution in structural parameters once cosmology is known

20. Theoretical Interpretation: Which is the physical mechanism governing biasing evolution? Gravity (Dekel and Rees 88 Tegmark & Peebles 98) Merging (Mo & White 96 Matarrese et al. 97 ) Istantaneous Star Formation (Blanton et al 02)

21. Field Reconstruction Technique

22. The PDF of mass:  (  ) Problem: we measure the PDF of galaxies in redshift space! Real Space Lognormal Model (Cole & Jones 1991, Springel et al. 2005)

23. Z=0.7-1.1 Z=1.1-1.5 Extraction of Biasing

24. Is the z-space lognormal PDF a good model ?  CDM Millenium Simulation (Virgo consortium)

25. Is the observed PDF representative?  CDM Millenium Simulation (Virgo consortium) 0<z<1.5

27. Linear Approximation Newtonian Regime Pressureless Matter fluid Adiabatic perturbation Linear Growth of CDM structures It exists an unstable growing solution 1) TESTING GRAVITY (GR) Fundamental variable describing the LSS structure Statistical Strategy : Analyze fluctuations moments

28. Evolution of low order moments Marinoni et al. A&A 2005 Fluctuations in the visible sector have frozen over ~2/3 of the history of the universe The Young universe was as much inhomogeneous as it is nowdays Second Moment Galaxy distribution was significantly non Gaussian even at early times Third Moment Marinoni et al. A&A 2007 Volume-limited sample M<-20+5log h

29. Un unprecedent convergence of results in cosmology over the last few years indicates that we live in a universe where: - ordinary matter is a minority (1/6) of all matter - matter is a minority (1/4) of all energy - geometry is spatially flat - Expansion is presently accelerated The major constituents of the universe and many of the detailed physical mechanisms yet remain to be understood. accelerating decelerating State of The Art

30. The outstanding problem : Dark Energy - The Fine Tuning Problem Particle physics theory currently provides no understanding of why the vacuum energy density is so small: - The Cosmic Coincidence Problem Theory provides no understanding of why the Dark Energy density is just now comparable to the matter density. - Nature : What is it? Is dark energy a scalar field ? a breakdown of General Relativity on large scales? Dark What do we know ? Smooth on cluster scales Accelerating the Universe {