Related papers: Observational challenges in dark energy models
Observations of distances to Type-Ia supernovae can be explained by cosmological models that include either a gigaparsec-scale void, or a cosmic flow, without the need for Dark Energy. Instead of invoking dark energy, these inhomogeneous…
We investigate the potential of a future supernova dataset, as might be obtained by the proposed SNAP satellite, to discriminate among different ``dark energy'' theories that describe an accelerating Universe. We find that many such models…
Over the last few years, low- and high-redshift observations set off a tension in the measurement of the present-day expansion rate, $H_0$. Adding to the riddle, observational data from the Planck mission point to a $3.4\sigma$ evidence for…
While recent supernova cosmology research has benefited from improved measurements, current analysis approaches are not statistically optimal and will prove insufficient for future surveys. This paper discusses the limitations of current…
We discuss the constraints on the time-varying equation of state for dark energy and the curvature of the universe using observations of type Ia supernovae from Riess et al. and the most recent Supernova Legacy Survey (SNLS), the baryon…
Since the discovery of the accelerated cosmic expansion, one of the most important tasks in observational cosmology is to determine the nature of the dark energy. We should build our understanding on a minimum of assumptions in order to…
Due to the deflection of light by density fluctuations along the line of sight, weak lensing is an unavoidable systematic uncertainty in the use of type Ia supernovae (SNe Ia) as cosmological distance indicators. We derive the expected weak…
Currently, the increasing availability of accurate cosmological probes leads to the emergence of tensions between data on the one hand and between theoretical predictions and direct observations on the other. Moreover, after 25 years since…
The persisting consistency of ever more accurate observational data with the predictions of the standard LCDM cosmological model puts severe constraints on possible alternative scenarios, but still does not shed any light on the fundamental…
A cosmological model with total density close to critical (and flat geometry), dominated by dark matter and dark energy of unknown nature, and consistent with the basic predictions of the inflationary scenario is a very good fit to a…
Type Ia Supernova(SN Ia) are a powerful, albeit not completely understood, tool for cosmology. Gaps in our understanding of their progenitors and detailed physics can lead to systematic errors in the cosmological distances they measure. We…
Given the persistence of various tensions in the "Cosmic Concordance" -- such as the "Hubble Tension", and possible departures from LambdaCDM time evolution -- seen from combinations of complementary data sets (e.g., Cosmic Microwave…
Over the last decade, cosmological observations have attained a level of precision which allows for detailed comparison with theoretical predictions. In this paper, we briefly review some studies of the current and prospected constraints…
The use of Type Ia supernovae as distance indicators led to the discovery of the accelerating expansion of the universe a decade ago. Now that large second generation surveys have significantly increased the size and quality of the…
Constantly accumulating observational data continue to confirm that about 70% of the energy density today consists of dark energy responsible for the accelerated expansion of the Universe. We present recent observational bounds on dark…
These lecture notes intend to form a short pedagogical introduction to the use of typical type Ia-Supernovae (hereafter SNIa) as standard candles to determine the energy density of the universe. Problems of principle for taking SNIa as…
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 are experiencing a period of extreme intellectual effervescence in the area of cosmology. A huge volume of observational data in unprecedented quantity and quality and a more consistent theoretical framework propelled cosmology to an era…
This contribution intends to give a pedagogical introduction to the topic of dark energy (the mysterious agent supposed to drive the observed late time acceleration of the Universe) and to various observational tests which require only…
We put forward a pressure-parametric model to study the tiny deviation from cosmological constant(CC) behavior of the dark sector accelerating the expansion of the Universe. Data from cosmic microwave background (CMB) anisotropies, baryonic…