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In this work, we derive a generalized modified Friedmann equation based on an entropy-area relation that incorporates established modifications, such as volumetric, linear, and logarithmic terms, in addition to novel entropic modifications that might yield to relevant cosmological implications at different stages of the evolution of the Universe. Some of these modifications are capable of mimicking the effects of dark energy and describing the current state of accelerated expansion of the Universe. We study particular cases of the generalized Friedmann equation and constrain the free parameters using observational datasets, including Hubble parameter measurements, baryon acoustic oscillations, and strong lensing systems. Our findings indicate that the proposed models align well with current observational data, particularly in low-redshift regimes; furthermore, these models are compatible with the value of $H_0$ obtained by the SH0ES program., Comment: 7 pages, 5 figures

We analyze cosmography as a tool to constrain modified gravity theories. We take four distinct models and obtain their parameters in terms of the cosmographic parameters favored by observational data of strong gravitational lensing. We contrast with the values obtained by direct comparison between each model and the observational data. In general, we find consistency between the two approaches at 2$\sigma$ for all models considered in this work. Our study bridges the gap between theoretical predictions of modified gravity and empirical observations of strong gravitational lensing, providing a simple methodology to test the validity of these models., Comment: 18 pages, 8 figures

Brane world models have shown to be promising to understand the late cosmic acceleration, in particular because such acceleration can be naturally derived, mimicking the dark energy behaviour just with a five dimensional geometry. In this paper we present a strong lensing joint analysis using a compilation of early-type galaxies acting as a lenses, united with the power of the well studied strong lensing galaxy cluster Abell\,1689. We use the strong lensing constraints to investigate a brane model with variable brane tension as a function of the redshift. In our joint analysis we found a value $n = 7.8^{+0.9}_{-0.5}$, for the exponent related to the brane tension, showing that $n$ deviates from a Cosmological Constant (CC) scenario (n=6). We obtain a value for the deceleration parameter, $q(z)$ today, $q(0)=-1.2^{+0.6}_{-0.8}$, and a transition redshift, $z_t=0.60\pm0.06$ (when the Universe change from an decelerated phase to an accelerated one). These results are in contrast with previous work that favors CC scenario, nevertheless our lensing analysis is in agreement with a formerly reported conclusion suggesting that the variable brane tension model is able to source a late cosmic acceleration without an extra fluid as in the standard one., Comment: ACCEPTED TO BE PUBLISHED IN THE EUROPEAN PHYSICAL JOURNAL C

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., Comment: Accepted for publication in MNRAS, 13 pages, 8 figures, 9 tables

Inspired by a new compilation of strong lensing systems, which consist of 204 points in the redshift range $0.0625< z_{l} < 0.958$ for the lens and $0.196< z_{s} < 3.595$ for the source, we constrain three models that generate a late cosmic acceleration: the $\omega$-cold dark matter model, the Chevallier-Polarski-Linder and the Jassal-Bagla-Padmanabhan parametrizations. Our compilation contains only those systems with early type galaxies acting as lenses, with spectroscopically measured stellar velocity dispersions, estimated Einstein radius, and both the lens and source redshifts. We assume an axially symmetric mass distribution in the lens equation, using a correction to alleviate differences between the measured velocity dispersion ($\sigma$) and the dark matter halo velocity dispersion ($\sigma_{DM}$) as well as other systematic errors that may affect the measurements. We have considered different sub-samples to constrain the cosmological parameters of each model. Additionally, we generate a mock data of SLS to asses the impact of the chosen mass profile on the accuracy of Einstein radius estimation. Our results show that cosmological constraints are very sensitive to the selected data: some cases show convergence problems in the estimation of cosmological parameters (e.g. systems with observed distance ratio $D^{obs}<0.5$), others show high values for the chi-square function (e.g. systems with a lens equation $D^{obs} >1$ or high velocity dispersion $\sigma > 276$ km s$^{-1}$). However, we obtained a fiduciary sample with 143 systems which improves the constraints on each tested cosmological model., Comment: 21 pages, 9 figures, Accepted for publication in MNRAS

Braneworld models have been proposed as a possible solution to the problem of the accelerated expansion of the Universe. The idea is to dispense the dark energy (DE) and drive the late-time cosmic acceleration with a five-dimensional geometry. Here, we investigate a brane model with variable brane tension as a function of redshift called chrono-brane. We propose the polynomial $\lambda=(1+z)^{n}$ function inspired in tracker-scalar-field potentials. To constrain the $n$ exponent we use the latest observational Hubble data from cosmic chronometers, Type Ia Supernovae from the full JLA sample, baryon acoustic oscillations and the posterior distance from the cosmic microwave background of Planck 2015 measurements. A joint analysis of these data estimates $n\simeq6.19$ which generates a DE-like or cosmological-constant-like term, in the Friedmann equation arising from the extra dimensions. This model is consistent with these data and can drive the Universe to an accelerated phase at late times., Comment: 7 pages, 6 figures, accepted for publication in Phys. Rev. D (Rapid Communication)

Motivated by an updated compilation of observational Hubble data (OHD) which consist of 51 points in the redshift range 0.07