THE ROAD TO DARK ENERGY

2008 ◽  
Vol 23 (17n20) ◽  
pp. 1346-1353
Author(s):  
DRAGAN HUTERER
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Parametric Methods ◽  
The Road ◽  
Dark Energy Survey ◽  
Energy Models ◽  
Scalar Field Models ◽  
General Scalar ◽  
Energy Survey ◽  
Observational Signature

I describe and critically evaluate a variety of methods, from simple parametrizations to non-parametric methods, to model the background expansion history in the presence of dark energy. Motivated by these approaches, I review the prospects of determining the properties of dark energy with future experiments, in particular the Dark Energy Survey (DES) and SuperNova/Acceleration Probe (SNAP). Finally, I outline the importance of being able to constrain whole classes of dark energy models, and present recent work that comprehensively studied the observational signature of general scalar field models.

scholarly journals QCD MODIFIED GHOST SCALAR FIELD DARK ENERGY MODELS

2013 ◽  
Vol 22 (05) ◽  
pp. 1350018 ◽  
Author(s):  
K. KARAMI ◽  
S. ASADZADEH ◽  
M. MOUSIVAND ◽  
Z. SAFARI
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Linear Perturbation ◽  
Density Parameter ◽  
Frw Cosmology ◽  
Frw Universe ◽  
Ghost Dark Energy ◽  
Energy Models ◽  
Scalar Field Models ◽  
Ghost Scalar Field

Within the framework of FRW cosmology, we study the QCD modified ghost scalar field models of dark energy (DE) in the presence of both interaction and viscosity. For a spatially nonflat FRW universe containing modified ghost dark energy (MGDE) and dark matter (DM), we obtain the equation of state of MGDE, the deceleration parameter as well as a differential equation governing the MGDE density parameter. We also investigate the growth of structure formation for our model in a linear perturbation regime. Furthermore, we reconstruct both the dynamics and potentials of the quintessence, tachyon, K-essence and dilaton scalar field DE models according to the evolution of the MGDE density.

scholarly journals POWER-LAW ENTROPY CORRECTED NEW HOLOGRAPHIC SCALAR FIELD MODELS OF DARK ENERGY WITH MODIFIED IR-CUTOFF

2011 ◽  
Vol 26 (33) ◽  
pp. 2487-2499 ◽  
Author(s):  
A. KHODAM-MOHAMMADI
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Kinetic Energy ◽  
Holographic Dark Energy ◽  
Matter Field ◽  
Dark Energy Density ◽  
Energy Models ◽  
Scalar Field Models ◽  
Phantom Barrier ◽  
Limiting Case

In this work, the PLECHDE model with Granda–Oliveros (G–O) IR-cutoff is studied. The evolution of dark energy density, deceleration and EoS parameters are calculated. I demonstrate that under a condition, our universe can accelerate near the phantom barrier at present time. We calculate these parameters also in PLECHDE at Ricci scale, when α = 2 and β = 1, and a comparison between Ricci scale, G–O cutoff and non-corrected HDE without matter field with G–O cutoff is done. The correspondence between this model and some scalar field of dark energy models is established. By this method, the evolutionary treatment of kinetic energy and potential for quintessence, tachyon, K-essence and dilaton fields, are obtained. I show that the results has a good compatibility with previous work in the limiting case of flat, dark dominated and non-corrected holographic dark energy.

Accreting Scalar-Field Models of Dark Energy Onto Morris-Thorne Wormhole

2016 ◽  
Vol 71 (10) ◽  
pp. 949-960
Author(s):  
Surajit Chattopadhyay ◽  
Antonio Pasqua ◽  
Irina Radinschi
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Equation Of State ◽  
Power Law ◽  
State Parameter ◽  
Suitable Choice ◽  
Energy Models ◽  
Scalar Field Models ◽  
Equation Of State Parameter ◽  
Phantom Phase

AbstractThe present paper reports a study on accreting tachyon, Dirac-Born-Infeld essence and h-essence scalar field models of dark energy onto Morris-Thorne wormhole. Using three different parameterisation schemes and taking $H\, = \,{H_0}\, + \,{{{H_1}} \over t}$, we have derived the mass of the wormhole for all of the three parameterisation schemes that are able to get hold of both quintessence and phantom behaviour. With suitable choice of parameters, we observed that accreting scalar field dark energy models are increasing the mass of the wormhole in the phantom phase and the mass is decreasing in the quintessence phase. Finally, we have considered accretion with power law form of scale factor and without any parameterisation scheme for the equation of state parameter and observed the fact that phantom-type dark energy supports the existence of wormholes.

scholarly journals Dark energy survey internal consistency tests of the joint cosmological probes analysis with posterior predictive distributions

2021 ◽  
Vol 503 (2) ◽  
pp. 2688-2705
Author(s):  
C Doux ◽  
E Baxter ◽  
P Lemos ◽  
C Chang ◽  
A Alarcon ◽  
...  
Keyword(s):  
Dark Energy ◽  
Internal Consistency ◽  
Goodness Of Fit ◽  
Small Scale ◽  
P Value ◽  
Posterior Predictive Distribution ◽  
Data Set ◽  
Dark Energy Survey ◽  
Data Vector ◽  
Energy Survey

ABSTRACT Beyond ΛCDM, physics or systematic errors may cause subsets of a cosmological data set to appear inconsistent when analysed assuming ΛCDM. We present an application of internal consistency tests to measurements from the Dark Energy Survey Year 1 (DES Y1) joint probes analysis. Our analysis relies on computing the posterior predictive distribution (PPD) for these data under the assumption of ΛCDM. We find that the DES Y1 data have an acceptable goodness of fit to ΛCDM, with a probability of finding a worse fit by random chance of p = 0.046. Using numerical PPD tests, supplemented by graphical checks, we show that most of the data vector appears completely consistent with expectations, although we observe a small tension between large- and small-scale measurements. A small part (roughly 1.5 per cent) of the data vector shows an unusually large departure from expectations; excluding this part of the data has negligible impact on cosmological constraints, but does significantly improve the p-value to 0.10. The methodology developed here will be applied to test the consistency of DES Year 3 joint probes data sets.

scholarly journals KiDS+VIKING-450 and DES-Y1 combined: Cosmology with cosmic shear

2020 ◽  
Vol 638 ◽  
pp. L1 ◽  
Author(s):  
S. Joudaki ◽  
H. Hildebrandt ◽  
D. Traykova ◽  
N. E. Chisari ◽  
C. Heymans ◽  
...  
Keyword(s):  
Dark Energy ◽  
Cosmic Microwave Background ◽  
Gravitational Lensing ◽  
Error Model ◽  
Calibration Error ◽  
Microwave Background ◽  
Weak Gravitational Lensing ◽  
Dark Energy Survey ◽  
Cosmic Shear ◽  
Energy Survey

We present a combined tomographic weak gravitational lensing analysis of the Kilo Degree Survey (KV450) and the Dark Energy Survey (DES-Y1). We homogenize the analysis of these two public cosmic shear datasets by adopting consistent priors and modeling of nonlinear scales, and determine new redshift distributions for DES-Y1 based on deep public spectroscopic surveys. Adopting these revised redshifts results in a 0.8σ reduction in the DES-inferred value for S​8, which decreases to a 0.5σ reduction when including a systematic redshift calibration error model from mock DES data based on the MICE2 simulation. The combined KV450+DES-Y1 constraint on S8 = 0.762−0.024+0.025 is in tension with the Planck 2018 constraint from the cosmic microwave background at the level of 2.5σ. This result highlights the importance of developing methods to provide accurate redshift calibration for current and future weak-lensing surveys.

scholarly journals Dark Energy Survey Year 1 Results: Wide-field mass maps via forward fitting in harmonic space

2020 ◽  
Vol 493 (4) ◽  
pp. 5662-5679 ◽  
Author(s):  
B Mawdsley ◽  
D Bacon ◽  
C Chang ◽  
P Melchior ◽  
E Rozo ◽  
...  
Keyword(s):  
Dark Energy ◽  
Mapping Technique ◽  
Harmonic Space ◽  
Wide Field ◽  
Direct Inversion ◽  
Dark Energy Survey ◽  
Central Regions ◽  
Fitting In ◽  
Energy Survey ◽  
Good Agreement

ABSTRACT We present new wide-field weak lensing mass maps for the Year 1 Dark Energy Survey (DES) data, generated via a forward fitting approach. This method of producing maps does not impose any prior constraints on the mass distribution to be reconstructed. The technique is found to improve the map reconstruction on the edges of the field compared to the conventional Kaiser–Squires method, which applies a direct inversion on the data; our approach is in good agreement with the previous direct approach in the central regions of the footprint. The mapping technique is assessed and verified with tests on simulations; together with the Kaiser–Squires method, the technique is then applied to data from the DES Year 1 data and the differences between the two methods are compared. We also produce the first DES measurements of the convergence Minkowski functionals and compare them to those measured in simulations.

Sign in / Sign up

Export Citation Format

Share Document