Related papers: Understanding the Optimal Redshift Range for the S…
Cosmic microwave background measurements have pushed to higher resolution, lower noise, and more sky coverage. These data enable a unique test of the early universe's expansion rate and constituents such as effective number of relativistic…
Gamma-ray bursts are the most energetic explosions in the Universe. They are detectable up to very high redshifts, therefore can be used to study the expansion rate of the Universe and to investigate the observational properties of dark…
In cosmography, cosmokinetics, and cosmology it is quite common to encounter physical quantities expanded as a Taylor series in the cosmological redshift z. Perhaps the most well-known exemplar of this phenomenon is the Hubble relation…
Images of the Hubble Ultra Deep Field are analyzed to obtain a catalog of galaxies for which the angular sizes, surface brightness, photometric redshifts, and absolute magnitudes are found. The catalog contains a total of about 4000…
The most intriguing question of modern astronomy is the question of our Universe formation. The Hubble diagram analysis with Type Ia Supernovae (SNe Ia) is widely used to estimate the cosmological parameters with high accuracy. The…
Over twenty years ago, Type Ia Supernovae (SNIa) observations revealed an accelerating Universe expansion, suggesting a significant dark energy presence, often modelled as a cosmological constant, \( \Lambda \). Despite its pivotal role in…
Measurements of the flux and redshifts of Type Ia supernovae have provided persuasive evidence that the expansion of the universe is accelerating. If true, then in the context of standard FRW cosmology this suggests that the energy density…
The concordance (LambdaCDM) model reproduces the main current cosmological observations assuming the validity of general relativity at all scales and epochs, the presence of cold dark matter, and of a cosmological constant, equivalent to a…
Using a model-independent analysis method which bases on the Lagrange mean value theorem for obtaining the derivative of the Hubble function, we analyze $H(z)$ parameter data with some restrictive conditions. We find that: (a) the Universe…
To probe the late evolution history of the Universe, we adopt two kinds of optimal basis systems. One of them is constructed by performing the principle component analysis (PCA) and the other is build by taking the multidimensional scaling…
We test the isotropy of the Hubble diagram. At small redshifts, this is possible without assumptions on the cosmic inventory and provides a fundamental test of the cosmological principle. At higher redshift we check for the self-consistency…
Despite vast improvements in the measurement of the cosmological parameters, the nature of dark energy and an accurate value of the Hubble constant (H$_0$) in the Hubble-Lema\^itre law remain unknown. To break the current impasse, it is…
The cosmological model is at present not tested between the redshift of the farthest observed supernovae (z ~ 1.4) and that of the Cosmic Microwave Background (z ~ 1,100). Here we introduce a new method to measure the cosmological…
A recent paper by Harmut Traunm\"uller shows that the most adequate equation to interpret the observations on magnitude and redshift from 892 type 1a supernovae would be mu = 5 log[(1+z) ln(1+z)] + const. We discuss this result which is…
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…
The acceleration of the expansion of the universe, ascribed to a dark energy, is one of the most intriguing discoveries in science. In addition to precise, systematics controlled data, clear, robust interpretation of the observations is…
Given a class of dark energy models, constraints from one set of cosmic acceleration observables make predictions for other observables. Here we present the allowed ranges for the expansion rate H(z), distances D(z), and the linear growth…
The discovery of dark energy by the first generation of high-redshift supernova surveys has generated enormous interest beyond cosmology and has dramatic implications for fundamental physics. Distance measurements using supernova explosions…
Observations of gamma-ray bursts up to $z\sim 9$ are best suited to study the possible evolution of the Universe equation of state at intermediate redshifts. We apply the Combo-relation to a sample of 174 gamma ray bursts to investigate…
We show that the dipole of the luminosity distance is a useful observational tool which allows us to determine the Hubble parameter as a function of the redshift H(z). We determine the number of supernovae needed to achieve a given…