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L. Perivolaropoulos leandros.physics.uoi.gr Department of Physics University of Ioannina

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Open page

Is ΛCDM the Correct Model?

L. Perivolaropouloshttp://leandros.physics.uoi.gr

Department of Physics

University of Ioannina

Structure of Talk

Model Classes - Key Questions

Geometric Constraints: Standard Rulers - Standard Candles

Comparison of Recent Standard Candle SnIa Data:-Figure of Merit-Consistency with ΛCDM-Consistency with Standard Rulers

Potential Conflicts of ΛCDM with Data:- Large Scale Velocity Flows- Cluster Halo Profiles- Emptiness of Voids - Brightness of High z SnIa

Dynamical Constraints: Linear Growth of Perturbations

Conclusion

Candidate Model Classes

Cosmological Constant

Expansion History

Gmn- L gmn = k Tmn

Dark Energy

Gmn = k (Tmmn+ T’μν)

Allowed Sector

Eq. of state evolution

Forbidden(ghosts)

Modified Gravity

G’mn = k Tmmn

Allowed Sector

Key Questions

Is General Relativity the correct theory on cosmological scales?

What is the most probable form of w(z) and what forms of w(z) can be excluded?

What is the consistency level of ΛCDM (GR + Λ) with cosmological observations?

What is the recent progress?

SnIa

Obs

GRB

Direct Probes of the Cosmic Metric:

Geometric Observational Probes

Direct Probes of H(z):

Luminosity Distance (standard candles: SnIa,GRB):

flat

Significantly less accurate probesS. Basilakos, LP, MBRAS ,391, 411, 2008arXiv:0805.0875

Angular Diameter Distance (standard rulers: CMB sound horizon, clusters):

Geometric Constraints

Parametrize H(z):

Chevallier, Pollarski, Linder

Minimize:

WMAP3+SDSS(2007) data

ESSENCE (+SNLS+HST) data

Standard Candles (SnIa)

Lazkoz, Nesseris, LPJCAP 0807:012,2008.arxiv: 0712.1232

Standard Rulers (CMB+BAO)

Recent SnIa Datasets

Q1: What is the Figure of Merit of each dataset?

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, 0908.2636

Figures of Merit

The Figure of Merit:Inverse area of the 2σ parameter contour.A measure of the effectiveness of the dataset in constraining the given parameters.

2σ Contours of Recent Datasets

GOLD06

SNLS

ESSENCE

UNION

CONSTITUTION

WMAP5+SDSS5

WMAP5+SDSS7

Consistency with ΛCDM

Trajectories of Best Fit Parameter Point

ESSENCE+SNLS+HST data

Ω0m=0.24

SNLS 1yr data

The trajectories of SNLS and Constitution clearly closer to ΛCDM for most values of Ω0m

Gold06 is the furthest from ΛCDM for most values of Ω0m

Q: What about the σ-distance (dσ) from ΛCDM?

The σ-distance to ΛCDM

ESSENCE+SNLS+HST data

Trajectories of Best Fit Parameter Point

Consistency with ΛCDM Ranking:

The σ-distance to Standard Rulers

ESSENCE+SNLS+HST

Trajectories of Best Fit Parameter Point

Consistency with Standard Rulers Ranking:

Consistency with Standard Rulers vs

Consistency with ΛCDM

Consistency with ΛCDM Ranking

Consistency with Standard Rulers Ranking:

Identical Ranking Sequence!(Independent Criteria)

The σ-distance to Dynamical Dark Energy

Trajectories of Best Fit Parameter Point

Consistency with Dynamical Dark Energy Ranking:

Comparing Ranking Sequences for

ΛCDM, Standard Rulers and Dynamical Dark Energy

Consistency with ΛCDM Ranking:

Consistency with Standard Rulers Ranking:

Identical Ranking Sequence

Tests Quality of SnIa Data

Reversed Ranking Sequence

Consistency with Dynamical Dark Energy Ranking

J. C. Bueno Sanchez, S. Nesseris, LP, 09082636

Trends of Geometric Probes

The 2σ parameter contour areas have improved by a factor of about 4 since 2005 while the number of filtered SnIa has increased by about the same factor. The consistency with standard rulers remains good (except for Gold06 dataset)

Flat, ΛCDM remains at 1σ (or less) distance from the best fit with trend to further improve consistency with geometric probes

Q: Which Dark Energy Probes have weak consistency with ΛCDM?

Puzzles for ΛCDM

From LP, 0811.4684

Large Scale Velocity Flows

- Predicted: On scale larger than 50 h-1Mpc Dipole Flows of 110km/sec or less. - Observed: Dipole Flows of more than 400km/sec on scales 50 h-1Mpc or larger.- Probability of Consistency:1%

R. Watkins et. al. , 0809.4041

Cluster and Galaxy Halo Profiles:

- Predicted: Shallow, low-concentration mass profiles- Observed: Highly concentrated, dense halos- Probability of Consistency:3-5%

Broadhurst et. al. ,ApJ 685, L5, 2008, 0805.2617, S. Basilakos, J.C. Bueno Sanchez, LP., 0908.1333, PRD, 80, 043530, 2009.

Bright High z SnIa:

- Predicted: Distance Modulus of High z SnIa close to best fit ΛCDM- Observed: Dist. Modulus of High z SnIa lower (brighter) than best fit ΛCDM- Probability of Consistency for Union and Gold06:3-6%

LP and A. Shafielloo , PRD 79, 123502, 2009, 0811.2802

The Emptiness of Voids:

- Predicted: Many small dark matter halos should reside in voids.- Observed: Smaller voids (10Mpc) look very empty (too few dwarf galaxies)- Probability of Consistency:3-5%

P.J.E. Peebles , astro-ph/0101127, Klypin et. al. APJ, 522, 82, 1999, astro-ph/9901240

Large Scale Velocity Flows

From R. Watkins, H. Feldman and M. J. Hudson, 0809.4041

The dipole moment of large scale velocity flows (bulk flow) extends on scales up to 100h-1Mpc with amplitudelarger than 400km/sec.

ΛCDM predicted amplitude on scale larger than 50h-1Mpc : 110km/sec

Cluster Halo Profiles

Navarro, Frenk, White, Ap.J., 463, 563, 1996

NFW profile:

From S. Basilakos, J.C. Bueno-Sanchez and LP, PRD, 80, 043530, 2009, 0908.1333.

ΛCDM prediction:

The predicted concentration parameter cvir is significantly smaller than the observed.

Data from:

Dynamical Constraints

Measure growth function of cosmological perturbations:

Horizon scales

Evolution of δ(sub-Hubble scales):

Horizon scales

James, Dutta, LP., 0903.5296

Parametrization:

Dynamical Constraints

Fit to LSS data:

ΛCDM

ΛCDM provides an excellent fit to the linear perturbations growth data

best fit

S. Nesseris, LP, Phys.Rev.D77:023504,2008

SUMMARY

The consistency of ΛCDM with geometric probes of accelerating expansion is very good and it appears to be further improving with time.

There are a few puzzling potential conflicts of ΛCDM specific cosmological data mainly related with dynamical large scale structure probes.

Data from dynamical probes on the linear growth of perturbations are currently not as constraining as geometric probes but they also have good consistency with ΛCDM.