Complexity in cosmic structures Francesco Sylos Labini Enrico
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 Sub-Poisson (ordered or super-homogeneous) Extremely fine-tuned distributions 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
Conditional correlation properties
Galaxy correlations: results Sylos Labini, F. , Montuori M. & Pietronero L. Phys Rep, 293, 66 (1998) Hogg et al. (SDSS Collaboration). Ap. J, 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….
Structure formation: the cosmological problem
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
- Slides: 13