Related papers: High Redshift Supernovae: Cosmological Implication…
Keeping in mind the current picture of an accelerating and flat Universe, some specific dynamical models of the cosmological term $\Lambda$ have been selected for investigating the nature of dark energy. Connecting the free parameters of…
I review the use of Type Ia supernovae (SNe Ia) for cosmological distance determinations. Low-redshift SNe Ia (z <~ 0.1) demonstrate that the Hubble expansion is linear, that H_0 = 65 +/- 2 (statistical) km/s/Mpc, and that the properties of…
We review various cosmological models with a local underdense region (local void) and the averaged models with the backreaction of inhomogeneities, which have been proposed to explain (without assuming a positive cosmological constant) the…
Recent observations of high redshift Supernovae at lower than expected value of the Hubble constant, widely interpreted as an evidence for accelerating expansion of the Universe, could alternatively be explained assuming a hyperbolic…
We investigate the cosmic thermal evolution with a vacuum energy which decays into photon at the low-redshift. We assume that the vacuum energy is a function of the scale factor that increases toward the early universe. We put on the…
We have identified seven (field) elliptical galaxies acting as strong gravitational lenses and have used them to measure cosmological parameters. To find the most likely value for Omega_m (= Omega_matter) and Lambda, we have used the…
Type Ia supernovae (SNIe) are generally accepted to act as standardisable candles, and their use in cosmology led to the first confirmation of the as yet unexplained accelerated cosmic expansion. Many of the theoretical models to explain…
The observation of SN 1997ff at redshift 1.7 has been claimed to refute alternative models such as grey dust or evolution for the faintness of distant supernovae, leaving only an accelerating Universe as a viable model. However, a very…
The main consequences of de Sitter Special Relativity to the Standard Cosmological Model of Physical Cosmology are examined. The cosmological constant Lambda appears, in this theory, as a manifestation of the proper conformal current, which…
An N + 1 dimensional quantum mechanical model for the origin of the universe results in a 58 e-fold inflation and a cosmological constant/vacuum energy density of the same order of magnitude as the critical density.
Tight constraints on cosmological parameters can be obtained with standard candles spanning a range of redshifts as large as possible. We propose to treat SN Ia and long Gamma-Ray Bursts (GRBs) as a single class of candles. Taking advantage…
Some serious faults in error analysis of observations for SNIa have been found. Redoing the same error analysis of SNIa, by our idea, it is found that the average total observational error of SNIa is obviously greater than $0.55^m$, so we…
The good match of the type Ia supernova (SNIa) Hubble Diagram to the prediction of a not-unreasonable cosmological world model shows that measurements of standard stars and their comparison with point sources down to m=25 mag is good to…
We examine the constraints that can be obtained on standard cold dark matter models from the most currently used data set: CMB anisotropies, type Ia supernovae and the SDSS luminous red galaxies. We also examine how these constraints are…
Currently, the $\Lambda$ Cold Dark Matter model, which relies on the existence of cold dark matter and a cosmological constant $\Lambda$, best describes the Universe. However, we lack information in the high-redshift ($z$) region between…
Type Ia supernovae (SNe Ia) currently provide the most direct evidence for an accelerating Universe and for the existence of an unknown "dark energy" driving this expansion. The 5-year Supernova Legacy Survey (SNLS;…
Supernova measurements have become a key ingredient in current determinations of cosmological parameters. These sources can however be used as standard candles only after correcting their apparent brightness for a number of effects. In this…
We have derived new bounds on the relativistic energy density in the Universe from cosmic microwave background (CMB), large scale structure (LSS), and type Ia supernova (SNI-a) observations. In terms of the effective number of neutrino…
The evidence for positive cosmological constant $\Lambda$ from Type Ia supernovae is reexamined. Both high redshift supernova teams are found to underestimate the effects of host galaxy extinction. The evidence for an absolute magnitude-…
The comoving sound horizon at the baryon drag epoch, $r_{d}$, encapsulates very important physical information about the pre-recombination era and serves as a cosmic standard ruler. On the other hand, the absolute magnitude of supernovae of…