Dark matter and Ricci-like holographic dark energy coupled through a quadratic interaction

We examine a spatially flat Friedmann-Robertson-Walker (FRW) universe filled with interacting dark matter and a modified holographic Ricci dark energy (MHRDE). The interaction term is selected as a significant rational function of the total energy density and its first derivative homogeneous of degree. We show that the effective one-fluid obeys the equation of state of a relaxed Chaplygin gas, then the universe turns to be dominated by pressureless dark matter at early times and undergoes an accelerated expansion in the far future driven by a strong negative pressure. Performing a X2-statistical analysis with the observational Hubble data and the Union2 compilation of SNe Ia, we place some constraints on cosmological parameters analyzing the feasibleness of the modified holographic Ricci ansatz. It turned that MHRDE gets the accelerated expansion faster than the ΛCDM model. Finally, a new model with a component that does not exchange energy with the interacting dark sector is presented for studying bounds on the dark energy at early times. © 2012 American Institute of Physics. ; Fil:Chimento, L.P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. ; Fil:Richarte, M.G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.