Related papers: Observational constraints on cosmology from modifi…
An alternative to dark energy as an explanation for the present phase of accelerated expansion of the Universe is that the Friedmann equation is modified, e.g. by extra dimensional gravity, on large scales. We explore a natural…
Recent supernovae of type Ia measurements and other astronomical observations suggest that our universe is in accelerating phase of evolution at the present epoch. While a dark energy of unknown form is usually proposed as the most feasible…
The recent observations of type Ia supernovae strongly support that the universe is accelerating now and decelerated in the recent past. This may be the evidence of the breakdown of the standard Friemann equation. We consider a general…
The accelerating expansion of the universe is the most surprising cosmological discovery in many decades, implying that the universe is dominated by some form of "dark energy" with exotic physical properties, or that Einstein's theory of…
The recent type Ia supernova data suggest that the universe is accelerating now and decelerated in recent past. This may provide the evidence that the standard Friedmann equation needs to be modified. We analyze in detail a new model in the…
There is mounting observational evidence that the expansion of our universe is undergoing an acceleration. A dark energy component has usually been invoked as the most feasible mechanism for the acceleration. However, it is desirable to…
Currently available Type Ia distant supernovae observed data seem to support evidence that the cosmic expansion of the universe is accelerating. This unexpected result is beyond any standard model of modern cosmology. The new concept…
The recent observations of type Ia supernovae suggest that the universe is accelerating now and decelerated in the recent past. This may be the evidence of the breakdown of the standard Friedmann equation. The Friedmann equation $H^2\sim…
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…
New observational constraints on the cosmic matter density $\Omega_m$ and an effectively redshift-independent equation of state parameter $w_x$ of the dark energy are obtained while simultaneously testing the strong and null energy…
The expansion rate of the Universe changes with time, initially slowing (decelerating) when the universe was matter dominated, because of the mutual gravitational attraction of all the matter in it, and more recently speeding up…
The existence of a dark energy component has usually been invoked as the most plausible way to explain the recent observational results. However, it is also well known that effects arising from new physics (e.g., extra dimensions) can mimic…
We confront Yukawa modified cosmology, proposed in arXiv:2304.11492 [Jusufi et al. arXiv:2304.11492], with data from Supernovae Type Ia (SNe Ia) and Hubble parameter (OHD) observations. Yukawa cosmology is obtained from a Yukawa-like…
The current observations are usually explained by an accelerating expansion of the present universe. However, with the present quality of the supernovae Ia data, the allowed parameter space is wide enough to accommodate the decelerating…
Context. Explaining the accelerated expansion of the Universe is one of the fundamental challenges in physics today. Cosmography provides information about the evolution of the universe derived from measured distances, assuming only that…
We constrain the evolution of the dark energy density from Cosmic Microwave Background, Large Scale Structure and Supernovae Ia measurements. While Supernovae Ia are most sensitive to the equation of state $w_0$ of dark energy today, the…
Fractional cosmology modifies the standard derivative to Caputo's fractional derivative of order $\mu$, generating changes in General Relativity. Friedmann equations are modified, and the evolution of the species densities depends on $\mu$…
Luminisity distances to the high-redshift Ia supernovas measured by the Supernova Cosmology Project team with the relativistic correction factors for redshift and time dilation led to the sensational conclusion about acceleration of…
A higher value of Hubble constant has been obtained from measurements with nearby Type Ia supernovae, than that obtained at much higher redshift. With the peculiar motions of their hosts, we find that the matter content at such low redshift…
Recent measurements of the parameters of the Concordance Cosmology Model ($\Lambda$CDM) done in the low-redshift Universe with Supernovae Ia/Cepheids, and in the distant Universe done with Cosmic Microwave Background (CMB) imply different…