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Related papers: Constraints on the Transition Redshift using Hubbl…

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A natural extension of the standard cosmological model are models that include curvature as a free parameter. In this work we study in detail the observational constraints on the non-flat $\Lambda CDM$ model using the two main geometric…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-15 Velasquez-Toribio , A. M , Magnago , A. dos R

The redshift $z_t$ and the jerk parameter $j_t$ of the transition epoch are constrained by using two model-independent approaches involving the direct expansion of the Hubble rate and the expansion of the deceleration parameter around…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-01 Anna Chiara Alfano , Salvatore Capozziello , Orlando Luongo , Marco Muccino

Directly comparing the 6 expansion rate measured by type Ia supernovae data and the lower bound on the expansion rate set by the strong energy conditions or the null hypothesis that there never exists cosmic acceleration, we see $3\sigma$…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-06 Yingjie Yang , Yungui Gong

The current tension between early- and late-Universe measurements of the Hubble constant ($H_0$), along with the still elusive nature of dark matter and dark energy, calls for model-independent probes of the Universe's expansion history.…

This paper aims to put constraints on the transition redshift $z_t$, which determines the onset of cosmic acceleration, in cosmological-model independent frameworks. In order to do that, we use the non-parametric Gaussian Process method…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-20 J. F. Jesus , R. Valentim , A. A. Escobal , S. H. Pereira

We propose a strategy to infer the transition redshift $z_{da}$, which characterizes the passage through the universe decelerated to accelerated phases, in the framework $f(R)$ gravities. To this end, we numerically reconstruct $f(z)$, i.e.…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-11 Salvatore Capozziello , Orlando Luongo

The supernovae Hubble diagram traces the expansion history of the universe, including the influence of dark energy. Its use to probe the cosmological model can fruitfully be guided by heuristic study of the features of the model curves. By…

Astrophysics · Physics 2007-05-23 Eric V. Linder

We compile a complete collection of reliable Hubble parameter $H(z)$ data to redshift $z \leq 2.36$ and use them with the Gaussian Process method to determine continuous $H(z)$ functions for various data subsets. From these continuous…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-04 Hai Yu , Bharat Ratra , Fa-Yin Wang

In this paper, linear first order expansion of deceleration parameter $q(z)=q_0+q_1(1-a)$ ($M_1$), constant jerk $j=j_0$ ($M_2$) and third order expansion of luminosity distance ($M_3$) are confronted with cosmic observations: SCP 307 SN…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-24 Lixin Xu , Wenbo Li , Jianbo Lu

Understanding the evolution of dark energy poses a significant challenge in modern cosmology, as it is responsible for the universe's accelerated expansion. In this study, we focus on a specific $f(T)$ cosmological model and analyze its…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-14 A. Zhadyranova , M. Koussour , S. Bekkhozhayev , V. Zhumabekova , J. Rayimbaev

We constrain the parameters describing the kinematical state of the universe using a cosmographic approach, which is fundamental in that it requires a very minimal set of assumptions (namely to specify a metric) and does not rely on the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Vincenzo Vitagliano , Jun-Qing Xia , Stefano Liberati , Matteo Viel

Gravitational transitions at low redshifts ($z_t<0.1$) have been recently proposed as a solution to the Hubble and growth tensions. Such transitions would naturally lead to a transition in the absolute magnitude $M$ of type Ia supernovae…

We study the constraints on dark energy equation of state $\omega^{X}$ and the deceleration parameter $q$ from the recent observational data including Hubble data and the cosmic microwave background (CMB) radiation by using a…

General Relativity and Quantum Cosmology · Physics 2015-03-26 Hassan Amirhashchi

We analyse the possibility that our Universe could be described by the model recently proposed by Melia & Shevchuk (2012), where the Hubble scale R_h=c/H is at all times equal to the distance ct that light has travelled since the Big Bang.…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-28 Maciej Bilicki , Marina Seikel

We use the deepest and most complete redshift catalog currently available (the Hubble Deep Field (HDF) North supplemented by new HDF South redshift data) to minimize residuals between photometric and spectroscopic redshift estimates. The…

Astrophysics · Physics 2016-08-30 M. Massarotti , A. Iovino , A. Buzzoni , D. Valls--Gabaud

We use simulated Hubble parameter data in the redshift range 0 \leq z \leq 2 to explore the role and power of observational H(z) data in constraining cosmological parameters of the {\Lambda}CDM model. The error model of the simulated data…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-11 Cong Ma , Tong-Jie Zhang

The Hubble parameter $H(z)$ is directly related to the expansion of our Universe. It can be used to study dark energy and constrain cosmology models. In this paper, we propose that $H(z)$ can be measured using fast radio bursts (FRBs) with…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-27 Q. Wu , Hai Yu , F. Y. Wang

We use Gaussian processes in combination with MCMC method to place constraints on cosmological parameters of three dark energy models including flat and curved FRW and Bianchi type I spacetimes. To do so, we use recently compiled 36…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-16 Hassan Amirhashchi , Soroush Amirhashchi

The strengthening of tensions in the cosmological parameters has led to a reconsideration of fundamental aspects of standard cosmology. The tension in the Hubble constant can also be viewed as a tension between local and early Universe…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-13 Purba Mukherjee , Konstantinos F. Dialektopoulos , Jackson Levi Said , Jurgen Mifsud

Within the Friedmann-Lema\^itre-Robertson-Walker (FLRW) framework, the Hubble constant $H_0$ is an integration constant. Thus, consistency of the model demands observational constancy of $H_0$. We demonstrate redshift evolution of best fit…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-28 Mohammad Malekjani , Ruairí Mc Conville , Eoin Ó Colgáin , Saeed Pourojaghi , M. M. Sheikh-Jabbari