COSMOLOGY AND COSMIC STRUCTURES

1. COSMOLOGY AND COSMIC STRUCTURES Antonaldo Diaferio Dipartimento di Fisica Generale Università degli Studi di Torino Current collaborators: Margaret J. Geller & Co.– Harvard-Smithsonian Center for Astrophysics Klaus Dolag – Max-Planck-Institut für Astrophysik Stefano Borgani & Co. - Universita' di Trieste Massimo Ramella – INAF, Oss. Astron. di Trieste Giuseppe Murante – INAF, Oss. Astron. di Torino Local group: Daniele Bertacca, Stefano Camera, Martina Giovalli, Luisa Ostorero, Ana Laura Serra Torino, 8 aprile 2008

2. Outline - Energy content of the Universe - Clusters of galaxies - Distribution of galaxies on large scales: galaxy formation - Alternative theories of gravity

3. THE MATTER/ENERGY CONTENT OF THE UNIVERSE ? ?

4. WHERE DO WE GET THIS RESULT FROM? vacuum energy density ΩΛ geometry mass density Ωm

5. Early astrophysical evidence of DM Zwicky 1933 Total cluster mass >> sum of masses of individual galaxies Coma cluster By using Newton/Einstein + virial theorem: GM = 3σ2R ≃100Σmgal

6. The 1980's: X-ray emission NGC2300 group Hydra cluster GM(<r) ~ kBTXr (hydro-static eq.) gas temperature m ~ 0.25

7. Dropping the dynamical equilibrium hypothesis. The 1990's: Gravitational lensing Weak lensing Strong lensing GM(<r) ~ αrc2 deflection angle m ~ 0.25

8. Dropping the dynamical equilibrium hypothesis: The caustic technique CL0024 Redshift diagram Sky Caustics Caustic amplitude = escape velocity m ~ 0.25 Diaferio & Geller 1997

9. CLUSTER MASSES: Comparing X-ray, Lensing and Caustics in three clusters 3D mass profile caustics X-ray lensing projected mass profile Diaferio et al. 2005

10. THE CENTER FOR ASTROPHYSICS REDSHIFT SURVEY (1978-1999) 20.000 galaxies Catalogue of galaxies with measured positions and distance (redshift) Sky projection redshift survey Milky Way 15000 km/s de Lapparent, Geller & Huchra 1986; Falco et al. 1999 redshift

11. The 2dF REDSHIFT SURVEY Colless et al 2001 The CfA RS

12. THE FORMATION OF COSMIC STRUCTURES: CDM by Ben Moore

13. THE FORMATION OF COSMIC STRUCTURES IN CDM MODELS: DM+Galaxies (semi-analytic modeling) z=3 z=2 z=1 z=0 Diaferio et al. 1999 (GIF sims.)

14. From a new redshift survey: SHELS(Geller et al.)

15. SIMULATIONS WITH ORDINARY (BARYONIC) MATTER: Diffuse IGM and Galaxies N-body/hydro-simulations gas density gas temperature Borgani et al. 2004

16. COSMIC STRUCTURES Forming a cluster stars gas density by Klaus Dolag

17. List of the non-gravitational processes adiabatic compression shock heating radiative heating and cooling thermal conduction reionization star formation and evolution feedback from supernovae explosion galactic winds chemical enrichment feedback from active galactic nuclei non-thermal processes (magnetic fields, cosmic ray production) sub- resolution processes

18. THE MATTER/ENERGY CONTENT OF THE UNIVERSE ? ?

19. The standard solution to DM Supersymmetry (beyond the SM) suggests a number of candidates: neutralinos, sneutrinos, gravitinos, axinos, ... but other candidates are axions, sterile neutrinos, “wimpzillas”, ... However: neither direct search (accelerators, energy recoil from nucleus hit) nor indirect search (gamma-ray, neutrino and anti-matter astronomy) has yet proved the existence of these particles.

20. The standard solution to DE (I) Rμν - ½ gμνR = 8πG/c4 Tμν + Λ gμν/c2 The DE fluid: ρΛ = -pΛ/c2 = Λc2/8πG The vacuum energy density interpretation ρΛ → ρv pΛ → pv = -ρvc2 ρv~ 10-48GeV4

21. Zoology of alternative gravities Einstein-Hilbert action: SEH=(16GN)-1 ∫ L (-g)1/2 d4x= (16GN)-1 ∫ (-g)1/2R d4x Can avoid DM & DE: metric theories L= f(R) where f is arbitrary (e.g. power laws, logarithms, etc.) additional fields scalar-tensor theories (introduced by Jordan 1955, Brans-Dicke 1961) TeVeS(Bekenstein 2004) STVG (Moffat 2006) (they have G and other constants varying with time) modification of the nature of the space-time geometry torsion ( not symmetric in : might be relevant for microphysics) non-symmetric metric g (e.g. Moffat: NGT nonsymmetric gravity theory1995, MSTG=metric skew tensor gravity 2005) generalized Riemann geometry (Weyl, who introduced the conformal transformations) additional symmetries Conformal gravity(Mennheim 2006) Can avoid DE only: from additional space-time dimension ofM-theory: brane cosmologies

22. UNIFIED DARK MATTER MODELS Ltot= (-g)1/2[R + L(X,)] + Lmatter X = (-1/2)DD w=p/(2Xp'-p); p=L e.g. generalized Chaplygin gas p=- @ high density: DM @ low density: DE Effective spherical potential V(r) = (½) exp(-2) (1+l2/r2) - (½) E2 exp[-)] ds2=-exp(2)dt2+exp(2)dr2+r2d

23. CONFORMAL GRAVITY BASICS action metric geodesic equation photons: E=0 massive particles: E>0 independent of 2 The Mannheim-Kazanas (MK) parameterization: gravitational potential deflection angle > 0  0 (Walker 1994, Edery & Paranjape 1998, Pireaux 2004a,b)

24. SIMULATION RESULTS X-ray surf. bright. evolution Temperature evolution 2 Mpc

25. Conclusions By assuming GR, the astrophysical observations imply an overwhelming amount of DM + DE compared to ordinary matter. This conclusion rests on the understanding of the astrophysical sources, and the control of systematics.