Download Presentation
## Complexity in cosmic structures

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -

**Complexity in cosmic structures**Francesco Sylos Labini Enrico Fermi Center & Institute for Complex Systems (ISC-CNR) Rome Italy A.Gabrielli, FSL, M. Joyce, L. Pietronero Statistical physics for cosmic structures Springer Verlag 2005**Early times density fields**COBE DMR, 1992 WMAP satellite 2006**Late times density fields**300 Mpc/h (2006) 150 Mpc/h (1990) 5 Mpc/h**The problem of cosmological structure formation**Initial conditions: Uniform distribution (small amplitude fluctuations) Dynamics: infinite self-gravitating system Final conditions: Stronlgy clustered, power-law correlations**Cosmological energy budget: the “standard model”**Non baryonic dark matter (e.g. CDM): -never detected on Earth -needed to make structures compatible with anisotropies Dark Energy -never detected on Earth -needed to explain SN data What do we know about dark matter ? Fundamental and observational constraints**Classification of uniform structures**Substantially Poisson (finite correlation length) Gas Super-Poisson (infinite correlation length) Critical system Extremely fine-tuned distributions Sub-Poisson (ordered or super-homogeneous) HZ tail**CMBR: results**Angular correlation function vanishes at > 60 deg (COBE/WMAP teams and Schwartz et al. 2004) Small quadrupole/octupole (COBE/WMAP teams)**Extendend Classification of homogeneous structures**Statistically isotropic and homogeneous Super-homogeneous Poisson-like Critical Fractals: isotropic but not homogeneous**Galaxy correlations: results**Sylos Labini, F., Montuori M.& Pietronero L. Phys Rep, 293, 66 (1998) Hogg et al. (SDSS Collaboration). ApJ, 624, 54 (2005)**Discrete gravitational N body problem**From order to complex structures: A Toy model Gravitational Dynamics generates Complex Structures Power law correlations Non Gaussian velocity distributions Probability distributions with “fat tails” (In)dipendence on IC and universal properties….**Summary**HZ tail: the only distinctive feature of FRW-IC in matter distribution is the behavior of the large scales tail of the real space correlation function Note yet observed in galaxy distributions Problem with large angle CMBR anisotropies Homogeneity scale: not yet identified in galaxy distributions Structures in N-Body simulations: too small and maybe different in nature from galaxy structures Basic propeerties of SGS