Talk detail

Participant	Mebarki, Noureddine
Institution	Mentouri University - Route Ain El Bey - Constantine - Constantine - Algiers

Session	AT1	Accepted		Order	Time
Talk	Oral abstract	Title	Some aspects of f(r) cosmology in an ellipsoid universe
Coauthors
Abstract	Friedman like equations in f(r) theories of gravity in a planar symmetric ellipsoid universe are derived and a dynamical study to determine behaviour of solutions near the resulted critical point is carried for an R^n model. Moreover, some dark energy scenarios with and without viscosity as well as the CMB quadrupole anomaly are also studied
Pdf file

Session	DE1	Accepted		Order	Time
Talk	Oral abstract	Title	Dynamical study of a viscous modified Chaplygin gas in classical and loop quantum cosmology
Coauthors
Abstract	A dynamical analysis of a viscous modified Chaplygin gas model within loop quantum cosmology (LQC) is discussed. It turns out that the model reproduces the main results of the standard model without assuming a priori the existence of cosmological constant. The problem related to fine-tuning is solved as the model is dynamical so it allows the energy density describing dark energy to decrease slowly to very small values and meets the observational data . In addition, the coincidence problem is solved too. At LQC background and at large scale the results found are the same as those of classical background and at small scale the Big Bang singularity problem is solved and replaced by a bounce. The universe in its evolution will undergo a decelerated expansion when dominated by dark matter modeled by VMCG before the decoupling dark energy/dark matter, the model then changes to behave like dark energy and the universe enters a phase of an accelerated expansion.
Pdf file

Session	DM1	Accepted		Order	Time
Talk	Oral abstract	Title	A New non cosmological redshift and its implicatiions on cosmological parameters and dark matter estimations
Coauthors
Abstract	The energy carried by gravitational waves created by the interaction between photons and constant magnetic fields is manifested as a new redshifts contributing to the total observed redshift of extra-galactic light. Cosmological simulations data are used to prove the significant impact of this effect. The analysis of synthetic observations created from those simulations has shown that this effect affects cosmological parameters estimations namely the Hubble parameter which it will be biased toward higher values. Contributions from this effect were not considered so far which may explain the discrepancy we have in the estimated values of cosmological parameters. Our results show also that this effect could be the origin of discordant redshifts observed in abnormal cases such as galaxy-quasar associations or Stephen’s quintet. The misinterpretation of our effect contributions as gravitational redshifts would result in over-estimation of dark matter composition of the universe.
Pdf file