Joint cosmological inference from galaxy surveys, the Cosmic Microwave   Background and the X-Ray Background
  We discuss cosmological inference from galaxy surveys, the X-Ray Background (XRB) and the Cosmic Microwave Background (CMB). We assume a family of Cold Dark Matter (CDM) models in a spatially flat universe with an initially scale-invariant spectrum and a cosmological constant. Joint analysis of the CMB and IRAS resdhift surveys yields as optimal parameters (for fixed Omega_b h^2 = 0.024): Omega_m = 1- \omega_lambda = 0.4, h = 0.53, Q = 17muK, and b_iras= 1.2. For the above parameters the normalisation and shape of the mass power-spectrum are sigma_8=0.7 and Gamma=0.15, and the age of the Universe is 16.5 Gyr. Assuming a standard CDM model, the joint IRAS and XRB analysis gives bias parameters of b_iras = 1.1 and b_x(z=0) = 2.6. When combining CMB and IRAS with XRB data we show that standard CDM cannot fit all three data sets. We also use these data sets to verify the Cosmological Principle and to constrain the fractal dimension of the universe on large scales. 
Ofer Lahav and Sarah L. Bridle