1. L. Perivolaropoulos http://leandros.physics.uoi.gr Department of Physics University of Ioannina Open page

2. Recent Geometric Probe Data (SnIa, CMB, BAO) Expansion Rate of the Universe is very similar to the rate predicted by ΛCDM There are some puzzling conflicts between ΛCDM predictions and LSS cosmological observations Q: Is there a concrete physical model where dark energy can have significant clustering properties on small scales? Yes. This naturally occurs in Scalar-Tensor cosmologies due to the direct coupling of the scalar field perturbations to matter induced curvature perturbations Large Scale Velocity Flows (3σ) Galaxy and Cluster Halo Profiles (2σ-3σ) There is a potential resolution of these conflicts if Dark Energy had clustering properties.

3. 3 Q2: What is the consistency of each dataset with ΛCDM? Q3: What is the consistency of each dataset with Standard Rulers? J. C. Bueno Sanchez, S. Nesseris, LP, JCAP 0911:029,2009, 0908.2636 Q1: What is the Figure of Merit of each dataset?

4. The Figure of Merit: Inverse area of the 2σ CPL parameter contour. A measure of the effectiveness of the dataset in constraining the given parameters. SNLS ESSENCE GOLD06 UNION CONSTITUTION WMAP5+SDSS5WMAP5+SDSS7

5. 5 The Figure of Merit: Inverse area of the 2σ CPL parameter contour. A measure of the effectiveness of the dataset in constraining the given parameters. SDSS5 SDSS7 Percival et. al.

6. 6 ESSENCE+SNLS+HST data SNLS 1yr data Trajectories of Best Fit Parameter Point The trajectories of SNLS and Constitution are clearly closer to ΛCDM for most values of Ω 0m Gold06 is the furthest from ΛCDM for most values of Ω 0m Q: What about the σ-distance (d σ ) from ΛCDM? Ω 0m =0.24

7. 7 ESSENCE+SNLS+HST data Trajectories of Best Fit Parameter Point Consistency with ΛCDM Ranking:

8. 8 Consistency with Standard Rulers Ranking: ESSENCE+SNLS+HST Trajectories of Best Fit Parameter Point

9. Large Scale Velocity Flows - Predicted: On scale larger than 50 h -1 Mpc Dipole Flows of 110km/sec or less. - Observed: Dipole Flows of more than 400km/sec on scales 50 h -1 Mpc or larger. - Probability of Consistency: 1% Cluster and Galaxy Halo Profiles: - Predicted: Shallow, low-concentration mass profiles - Observed: Highly concentrated, dense halos - Probability of Consistency: 3-5% From LP, 0811.4684 R. Watkins et. al., 0809.4041 Broadhurst et. al.,ApJ 685, L5, 2008, 0805.2617, S. Basilakos, J.C. Bueno Sanchez, LP., 0908.1333, PRD, 80, 043530, 2009.

10. 10 NFW profile: ΛCDM prediction: The predicted concentration parameter c vir is significantly smaller than the observed. From S. Basilakos, J.C. Bueno-Sanchez and LP, PRD, 80, 043530, 2009, 0908.1333. Data from: Navarro, Frenk, White, Ap.J., 463, 563, 1996

11. 11 NFW profile: clustered dark energy Clustered Dark Energy can produce more concentrated halo profiles From S. Basilakos, J.C. Bueno-Sanchez and LP, PRD, 80, 043530, 2009, 0908.1333. Data from: Navarro, Frenk, White, Ap.J., 463, 563, 1996

12. Q: Is there a model with a similar expansion rate as ΛCDM but with significant clustering of dark energy? A: Yes. This naturally occurs in Scalar-Tensor cosmologies due to the direct coupling of the scalar field perturbations to matter induced curvature perturbations

13. Rescale ΦUnits: General Relativity: Generalized Einstein-Field Equations:

14. Flat FRW metric: Generalized Friedman equations:

15. Advantages: Natural generalizations of GR (superstring dilaton, Kaluza-Klein theories) General theories (f(R) and Brans-Dicke theories consist a special case of ST) Potential for Resolution of Coincidence Problem Natural Super-acceleration (w eff <-1) Amplified Dark Energy Perturbations Constraints: Solar System Cosmology

16. J. C. Bueno Sanchez., LP in preparation

17. Thawing Minimally Coupled Quintessence

18. Oscillations (due to coupling to ρ m ) and non-trivial evolution

19. Effective Equation of State: Scalar-Tensor (λ f =5) Minimal Coupling (λ f =0) w eff z

20. Perturbed FRW metric (Newtonian gauge): Generalized Einstein-Field Equations:

21. No suppression on small scales!

22. Suppressed fluctuations on small scales! Sub-Hubble GR scales (as in minimally coupled quintessence)

23. Scalar Field Perturbations Minimal Coupling (F=1) Scale = 30 h -1 Mpc Non-Minimal Coupling (F=1-λ f 2 Φ 2 )

24. Matter Density Perturbations Minimal Coupling (F=1)Non-Minimal Coupling (F=1-λ f 2 Φ 2 )

25. Scalar Field Density Perturbations Minimal Coupling (F=1)Non-Minimal Coupling (F=1-λ f 2 Φ 2 )

26. Scale Dependence of Dark Energy/Dark Matter Perturbations Minimal Coupling (F=1)Non-Minimal Coupling (F=1-λ f Φ 2 ) Dramatic Difference on sub-Hubble scales!

27. Scale Dependence of Dark Energy Perturbations Minimal Coupling (F=1)Non-Minimal Coupling (F=1-λ f Φ 2 ) Dramatic Difference on sub-Hubble scales!

28. Recent Geometric Probe Data (SnIa, CMB, BAO) are increasingly consistent with ΛCDM and with each other. The Constitution SnIa dataset is of the highest quality and is also the most consistent with ΛCDM and with Standard Rulers. Observed Cluster Halo Profiles are significantly more concentrated than predicted by ΛCDM. This may be interpreted as a trace of an additional clustering energy component in the halo. Scalar Tensor cosmologies are generic extensions of GR. They naturally allow for crossing of the w=-1 line and amplified dark energy perturbations on sub-Hubble scale by a factor of more than 10 4 compared to quintessence. This may help in the resolution of the cluster profile puzzle.