Formation of Large Structures in the Acceleration Universe with a Hybrid Expansion Law


Astrophysics Department, Physics Faculty, University of Tabriz, Tabriz, Iran


In the current paper, we have studied the effect of dark energy on for-mation where dark energy exists in the background. For this purpose, we used both WMAP9 and Planck data to study how the radius changes with redshift in these mod-els. We used different data sets to fix the cosmological parameters to obtain a solution for a spherical region under collapse. The mechanism of structure formation for dark and baryonic matter is different. When processed by gravitational instability, den-sity perturbations have given rise to collapsed dark matter structures, called halos. These dark matter halos offer the backdrop for the subsequent formation of all col-lapsed baryonic structures, including stars, galaxies, and galaxy clusters. In Planck Data forΛCDM, with the presence of dark energy in the background, the formation of baryonic matter is delayed. Therefore, it is a factor for the largening of the baryonic matter radius. Accompanying dark energy is entailing an increment of dark matter virial radius. For WACDM Data, dark energy alongside time-dependent parameter of state and baryon acoustic oscillations are the reasons for the delay of dark matter formation and the radius reduction. Due to the lack of data without baryonic acoustic waves in the background, we are left unable to delineate its impact on the structures. In WCDM(BAO +H0) and WCDM(H0), the lack of BAO shows a critical role in the delaying of baryonic matter structure formation. Respectively, it causes growing virial radius of dark matter. BAO, without taking dark energy into accounts, is the reason for the increasing and decresing of radius of dark and baryonic matter. It also delays baryonic matter formation. In ΛCDM(BAO +H0) and ΛCDM(H0), We have studied ΛCDM data for standard model under two circumstances: (a) ΛCDM(BAO + H0),(b) ΛCDM(H0) data. Dark energy in this data delays formation and intensifies virial radius of baryonic matter. Our studies show WCDM andΛCDM have the same effect on formation if we do not consider dark energy in BG. Planck data, in comparing with WMAP, has important role in describing standard model.