scholarly journals Phantom Braneworld and the Hubble Tension

2021 ◽  
Vol 923 (2) ◽  
pp. 212
Author(s):  
Satadru Bag ◽  
Varun Sahni ◽  
Arman Shafieloo ◽  
Yuri Shtanov
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Cosmic Microwave Background ◽  
Data Sets ◽  
Microwave Background ◽  
Effective Equation ◽  
Induced Gravity ◽  
Cosmic Evolution ◽  
Local Measurements ◽  
Braneworld Model

Abstract Braneworld models with induced gravity exhibit phantom-like behavior of the effective equation of state of dark energy. They can, therefore, naturally accommodate higher values of H 0, preferred by recent local measurements while satisfying the cosmic microwave background constraints. We test the background evolution in such phantom braneworld scenarios with the current observational data sets. We find that the phantom braneworld prefers a higher value of H 0 even without the R19 prior, thereby providing a much better fit to the local measurements. Although this braneworld model cannot fully satisfy all combinations of cosmological observables, among existing dark energy candidates the phantom brane provides one of the most compelling explanations of cosmic evolution.

scholarly journals Mapping the Dark Energy Equation of State

2005 ◽  
Vol 216 ◽  
pp. 59-66
Author(s):  
Eric V. Linder
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Energy Density ◽  
Cosmic Microwave Background ◽  
Structure Formation ◽  
Energy Equation ◽  
Microwave Background ◽  
Redshift Surveys ◽  
Expansion Of The Universe ◽  
The Universe

The acceleration of the expansion of the universe has deep implications for structure formation, the composition of the universe, and its fate. Roughly 70% of the energy density is in a dark energy, whose nature remains unknown. Mapping the expansion history through supernovae, mapping the geometry of the universe and formation of structure through redshift surveys, and mapping the distance to recombination through the cosmic microwave background provide complementary, precise probes of the equation of state of the dark energy. Together these next generation maps of the cosmos can reveal not only the value today, but the redshift variation, of the equation of state, providing a critical clue to the underlying physics.

PROBE OF THE INTERACTION BETWEEN DARK SECTORS ON THE LARGE SCALE COSMIC MICROWAVE BACKGROUND ANISOTROPIES

2011 ◽  
Vol 20 (10) ◽  
pp. 2121-2124
Author(s):  
JIAN-HUA HE ◽  
BIN WANG
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cosmic Microwave Background ◽  
Significant Influence ◽  
Large Scale ◽  
Power Spectra ◽  
Data Sets ◽  
Late Time ◽  
Microwave Background ◽  
Coincidence Problem

In this review, we study the signature of the interaction between dark energy (DE) and dark matter (DM) on the large-scale CMB anisotropies. We find the interaction has significant influence on the late time Integrated Sachs Wolfe effect (ISW). The positive coupling could suppress the low-l part of the power spectra. We also confront the interacting models with WMAP 5-year as well as other data sets. We find that these models are well-fitted and in 1σ range, the constrained coupling between dark sectors can solve the coincidence problem.

scholarly journals Constraining Cosmic Microwave Background Temperature Evolution With Sunyaev–Zel’Dovich Galaxy Clusters from the Atacama Cosmology Telescope

2021 ◽  
Vol 922 (2) ◽  
pp. 136
Author(s):  
Yunyang Li ◽  
Adam D. Hincks ◽  
Stefania Amodeo ◽  
Elia S. Battistelli ◽  
J. Richard Bond ◽  
...  
Keyword(s):  
Cosmic Microwave Background ◽  
Temperature Evolution ◽  
Data Sets ◽  
Microwave Background ◽  
Effective Equation ◽  
Atacama Cosmology Telescope ◽  
Model Combining ◽  
Cosmic Microwave Background Temperature ◽  
The Standard Model ◽  
Background Temperature

Abstract The Sunyaev–Zel’dovich (SZ) effect introduces a specific distortion of the blackbody spectrum of the cosmic microwave background (CMB) radiation when it scatters off hot gas in clusters of galaxies. The frequency dependence of the distortion is only independent of the cluster redshift when the evolution of the CMB radiation is adiabatic. Using 370 clusters within the redshift range 0.07 ≲ z ≲ 1.4 from the largest SZ-selected cluster sample to date from the Atacama Cosmology Telescope, we provide new constraints on the deviation of CMB temperature evolution from the standard model α = 0.017 − 0.032 + 0.029 , where T ( z ) = T 0 1 + z 1 − α . This result is consistent with no deviation from the standard adiabatic model. Combining it with previous, independent data sets we obtain a joint constraint of α = −0.001 ± 0.012. Attributing deviation from adiabaticity to the decay of dark energy, this result constrains its effective equation of state w eff = − 0.998 − 0.010 + 0.008 .

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 Nonparametric reconstruction of the dark energy equation of state from diverse data sets

2011 ◽  
Vol 84 (8) ◽  
Author(s):  
Tracy Holsclaw ◽  
Ujjaini Alam ◽  
Bruno Sansó ◽  
Herbie Lee ◽  
Katrin Heitmann ◽  
...  
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Energy Equation ◽  
Data Sets ◽  
Diverse Data

scholarly journals Decaying Dark Energy in Light of the Latest Cosmological Dataset

Symmetry ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 372 ◽  
Author(s):  
Ivan de Martino
Keyword(s):  
Dark Energy ◽  
Cosmic Microwave Background ◽  
Parameter Space ◽  
Hubble Constant ◽  
Two Dimensions ◽  
Matter Density ◽  
Microwave Background ◽  
Energy Models ◽  
Cosmic Microwave Background Temperature ◽  
Background Temperature

Decaying Dark Energy models modify the background evolution of the most common observables, such as the Hubble function, the luminosity distance and the Cosmic Microwave Background temperature–redshift scaling relation. We use the most recent observationally-determined datasets, including Supernovae Type Ia and Gamma Ray Bursts data, along with H ( z ) and Cosmic Microwave Background temperature versus z data and the reduced Cosmic Microwave Background parameters, to improve the previous constraints on these models. We perform a Monte Carlo Markov Chain analysis to constrain the parameter space, on the basis of two distinct methods. In view of the first method, the Hubble constant and the matter density are left to vary freely. In this case, our results are compatible with previous analyses associated with decaying Dark Energy models, as well as with the most recent description of the cosmological background. In view of the second method, we set the Hubble constant and the matter density to their best fit values obtained by the Planck satellite, reducing the parameter space to two dimensions, and improving the existent constraints on the model’s parameters. Our results suggest that the accelerated expansion of the Universe is well described by the cosmological constant, and we argue that forthcoming observations will play a determinant role to constrain/rule out decaying Dark Energy.

scholarly journals PARAMETRIZATION OF k-ESSENCE AND ITS KINETIC TERM

2006 ◽  
Vol 21 (21) ◽  
pp. 1683-1689 ◽  
Author(s):  
HUI LI ◽  
ZONG-KUAN GUO ◽  
YUAN-ZHONG ZHANG
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Kinetic Term ◽  
State Function ◽  
Effective Equation

We construct the non-canonical kinetic term of a k-essence field directly from the effective equation of state function wk(z), which describes the properties of the dark energy. Adopting the usual parametrizations of equation of state, we numerically reproduce the shape of the non-canonical kinetic term and discuss some features of the constructed form of k-essence.

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