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Register a new userConstraining deceleration, jerk and transition redshift using cosmic chronometers, Type Ia supernovae and ISW effect
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Added by
Syed Faisal ur Rahman
Publication date
2021
fields
Physics
and research's language is
English
Authors
Syed Faisal ur Rahman
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In this study we present constraints on the deceleration (q) and jerk (j) parameters using the late time integrated Sachs-Wolfe effect, type Ia supernovae, and H(z) data . We first directly measure the deceleration and jerk parameters using the cosmic chronometers data with the Taylor series expression of H(z).However, due to the unusual variations in the deceleration parameter with slight changes in other parameters like snap (s) and lerk (l), we found that direct measurements using the series expression of the H(z) is not a suitable method for non-Lambda-CDM models and so we will need to derive the deceleration parameter after constraining density parameters and dark energy equation of state parameters. Then we present derived values of the deceleration parameter from Lambda CDM, WCDM and CPL models. We also discuss the transition redshift (zt) in relation with the deceleration parameter.
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We carry out a test of the cosmic distance duality relation using a sample of 52 SPT-SZ clusters, along with X-ray measurements from XMM-Newton. To carry out this test, we need an estimate of the luminosity distance ($D_L$) at the redshift of the cluster. For this purpose, we use three independent methods: directly using $D_L$ from the closest Type Ia Supernovae from the Union 2.1 sample, non-parametric reconstruction of $D_L$ using the same Union 2.1 sample, and finally using $H(z)$ measurements from cosmic chronometers and reconstructing $D_L$ using Gaussian Process regression. We use four different functions to characterize the deviations from CDDR. All our results for these ($4 times 3$) analyses are consistent with CDDR to within 1$sigma$.
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Using a new sub-sample of observed strong gravitational lens systems, for the first time, we present the equation for the angular diameter distance in the $y$-redshift scenario for cosmography and use it to test the cosmographic parameters. In addition, we also use the observational Hubble data from cosmic chronometers and a Joint analysis of both data is performed. Among the most important conclusions are that this new analysis for cosmography using Strong Lensing Systems is equally competitive to constrain the cosmographic parameters as others presented in literature. Additionally, we present the reconstruction of the effective equation of state inferred from our samples, showing that at $z=0$ those reconstructions from Strong Lensing Systems and Joint analysis are in concordance with the standard model of cosmology.
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