Abstract Details
| Name: Nisha Rani Affiliation: University of Delhi Conference ID: ASI2016_658 Title : Parametric and nonparametric contraints on Transition redshift Authors and Co-Authors : Deepak Jain, Deen Dayal Upadhyaya College, University of Delhi, New Delhi 110015, India Shobhit Mahajan, Department of Physics & Astrophysics, University of Delhi, New Delhi 110007, India Amitabha Mukherjee, Department of Physics & Astrophysics, University of Delhi, New Delhi 110007, India Nilza Pires, Departamento de FÃsica Teórica e Experimental, UFRN, Campus Universitário, Natal, RN 59072-970, Brazil Abstract Type : Oral Abstract Category : General Relativity and Cosmology Abstract : The cosmokinematics approach is used to study the accelerated expansion of the Universe. This approach depends only on the assumption that Universe is described by the FRW metric and is homogeneous and isotropic at large scales. We parametrize the deceleration parameter, $q(z)$, to constrain the transition redshift ($z_t$) at which the expansion of the Universe goes from a decelerating to an accelerating phase. We parametrize $q(z)$ in three ways namely, $q_\I(z)=q_{\textnormal{\tiny\textsc{1}}}+q_{\textnormal{\tiny\textsc{2}}}z$, $q_\II (z) = q_\3 + q_\4 \ln (1 + z)$ and $q_\III(z)=\frac{1}{2}+\frac{q_{\textnormal{\tiny\textsc{5}}}}{(1+z)^2}$. A joint analysis of the age of galaxies, strong lensing and supernovae Ia data indicates that the transition redshift is less than unity. $z_t$ is further constrain using nonparametric method (LOESS+SIMEX). This also gives $z_t<1$. Value of $z_t$ from parametric and nonparametric method is consistent with each other. |