scholarly journals Hubble Expansion as an Einstein Curvature

2021 ◽  
Author(s):  
John Herbert Marr
Keyword(s):  
General Relativity ◽  
Acoustic Oscillation ◽  
Angular Diameter Distance ◽  
Hubble Expansion ◽  
Spacetime Manifold ◽  
Christoffel Symbols ◽  
Type Ia ◽  
Comparable Accuracy ◽  
Ia Supernovae ◽  
Rms Errors

Hubble expansion may be considered as a velocity per photon travel time rather than as velocity or redshift per distance. Dimensionally, this is an acceleration and will have an associated curvature of space under general relativity. This paper explores this theoretical curvature as an extension to the spacetime manifold of general relativity, generating a modified solution with three additional non-zero Christoffel symbols, and a reformulated Ricci tensor and curvature. The observational consequences of this reformulation were compared with the ΛCDM model for luminosity distance using the extensive type Ia supernovae (SNe Ia) data with redshift corrected to the CMB, and for angular diameter distance with the recent baryonic acoustic oscillation (BAO) data. For the SNe Ia data, the modified GR and ΛCDM models differed by −0.15+0.11μB mag. over zcmb=0.01−1.3, with overall weighted RMS errors of ±0.136μB mag for modified GR and ±0.151μB mag for ΛCDM espectively. The BAO measures spanned a range z=0.106−2.36, with weighted RMS errors of ±0.034 Mpc with H0=67.6±0.25 for the modified GR model, and ±0.085 Mpc with H0=70.0±0.25 for the ΛCDM model. The derived GR metric for this new solution describes both the SNe Ia and the BAO observations with comparable accuracy to ΛCDM without requiring the inclusion of dark matter or w’-corrected dark energy.

Overview of astroparticle physics and dark matter searches

2007 ◽  
Vol 22 (31) ◽  
pp. 5735-5746
Author(s):  
Nathalie Palanque-Delabrouille
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Acoustic Oscillation ◽  
Type Ia Supernovae ◽  
Clusters Of Galaxies ◽  
Astroparticle Physics ◽  
The Status ◽  
Type Ia ◽  
Ia Supernovae ◽  
The Impact

We present a general overview of recent results in the searches for dark matter and dark energy. We discuss the observation of the collision between two clusters of galaxies, and the impact this has on the relevance of dark matter. We then present the final results from microlensing experiments, which aimed at detecting dark baryonic objects in the halo of our galaxy, and the status of direct searches for WIMPs. We present the evidence for dark energy which initially comes from experiments dedicated to the study of distant type Ia supernovae. The measure of the baryon acoustic oscillation, an independent probe of the evolution of our universe that has recently brought interesting constraints, is finally described.

CONSTRAINT ON THE KINEMATICAL AND DYNAMICAL MODEL FROM THE LATEST OBSERVATIONAL DATA

2010 ◽  
Vol 25 (36) ◽  
pp. 3033-3046 ◽  
Author(s):  
JIANBO LU ◽  
YABO WU ◽  
LIXIN XU
Keyword(s):  
Observational Data ◽  
Acoustic Oscillation ◽  
Sloan Digital Sky Survey ◽  
Dynamical Model ◽  
Sky Survey ◽  
Type Ia ◽  
Redshift Survey ◽  
Galaxy Redshift ◽  
Ia Supernovae ◽  
Field Galaxy

The kinematical model j(z) = j0and dynamical model wde(z) = w0, are constrained from the latest observational data: Union2 data including 557 type Ia supernovae (SNIa), 15 observational Hubble data (OHD), baryon acoustic oscillation (BAO) data from Sloan Digital Sky Survey (SDSS) and Two-degree Field Galaxy Redshift Survey (2dFGRS) and CMB data from seven-year WMAP. We get the current values of deceleration parameter q0, jerk parameter j0, dimensionless matter density Ωm, equation of state for dark energy w0and transition redshift zT. Furthermore, it is shown that for both kinematical and dynamical models, the constraint results support for the cosmic concordance model, ΛCDM.

Cosmological implications of the dark matter equation of state

2017 ◽  
Vol 26 (03) ◽  
pp. 1750013 ◽  
Author(s):  
Weiqiang Yang ◽  
Hang Li ◽  
Yabo Wu ◽  
Jianbo Lu
Keyword(s):  
Dark Matter ◽  
Equation Of State ◽  
Cold Dark Matter ◽  
Evolution Equations ◽  
State Parameter ◽  
Acoustic Oscillation ◽  
Text Data ◽  
Equation Of State Parameter ◽  
Type Ia ◽  
Ia Supernovae

In this paper, we study a model which is composed of the cosmological constant and dark matter with nonzero equation of state parameter, which could be called as [Formula: see text]wDM. In the synchronous gauge, we obtain the perturbation equations of dark matter, and deduce the evolution equations of growth factor about the dark matter and baryons. Based on the Markov Chain Monte Carlo (MCMC) method, we constrain this model by the recently available cosmic observations which include cosmic microwave background (CMB) radiation, baryon acoustic oscillation (BAO), type Ia supernovae (SNIa) and [Formula: see text] data points from redshift-space distortion (RSD). The results present a tighter constraint on the model than the case without [Formula: see text] data. In 3[Formula: see text] regions, we find the dark matter equation of state parameter [Formula: see text]. The currently available cosmic observations do not favor the nonzero dark matter equation of state parameter, no deviation from the lambda cold dark matter ([Formula: see text]CDM) model is found in 1[Formula: see text] region.

Accelerating universe with the effect of anisotropy on dark energy model in the framework of Brans–Dicke theory

2020 ◽  
Vol 17 (13) ◽  
pp. 2050194
Author(s):  
H. Hossienkhani ◽  
N. Azimi ◽  
Z. Zarei
Keyword(s):  
Dark Energy Model ◽  
State Parameter ◽  
Acoustic Oscillation ◽  
Accelerating Universe ◽  
Anisotropic Universe ◽  
Text Data ◽  
Type Ia ◽  
Best Fitting ◽  
Ia Supernovae ◽  
The Universe

This study set out to investigate the effect of anisotropy on the [Formula: see text]CDM model in the framework of Brans−Dicke theory. To this end, astrophysical constraints on this model using current available data including type Ia supernovae (SNIa), the Baryon Acoustic Oscillation (BAO), and the Hubble parameter [Formula: see text] data were deployed. Here, we present combined results from these probes, deriving constraints on [Formula: see text] of [Formula: see text]CDM model and its anisotropy energy density in an anisotropic universe. It is found that [Formula: see text] can be constrained by the [Formula: see text] data, with the best fitting value [Formula: see text] for the Brans–Dicke cosmology. We extend our study to the case of [Formula: see text]CDM model in an anisotropic universe and Brans–Dicke framework and find out that the equation of state parameter ([Formula: see text]) cannot cross the phantom line and eventually the universe approaches a quintessence era.

scholarly journals Confronting Einstein Yang Mills Higgs dark energy in light of observations

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Debabrata Adak
Keyword(s):  
Dark Energy ◽  
Background Radiation ◽  
Higgs Field ◽  
Acoustic Oscillation ◽  
Accelerated Expansion ◽  
Shift Parameter ◽  
Yang Mills ◽  
Microwave Background Radiation ◽  
Type Ia ◽  
Ia Supernovae

AbstractWe study the observational aspects of Einstein Yang Mills Higgs dark energy model and constrain the parameters space from the latest observational data from type Ia supernovae, observational Hubble data, baryon acoustic oscillation data and cosmic microwave background radiation shift parameter data. It is found from the analysis of data that the Higgs field in presence of gauge fields can successfully describe the present accelerated expansion of the universe consistent with the astrophysical observations.

scholarly journals A measurement of the Hubble constant from angular diameter distances to two gravitational lenses

Science ◽  
2019 ◽  
Vol 365 (6458) ◽  
pp. 1134-1138 ◽  
Author(s):  
Inh Jee ◽  
Sherry H. Suyu ◽  
Eiichiro Komatsu ◽  
Christopher D. Fassnacht ◽  
Stefan Hilbert ◽  
...  
Keyword(s):  
Hubble Constant ◽  
Angular Diameter ◽  
Type Ia Supernovae ◽  
Gravitational Lenses ◽  
Angular Diameter Distance ◽  
Local Expansion ◽  
Type Ia ◽  
Ia Supernovae ◽  
The Universe ◽  
Recession Velocity

The local expansion rate of the Universe is parametrized by the Hubble constant, H0, the ratio between recession velocity and distance. Different techniques lead to inconsistent estimates of H0. Observations of Type Ia supernovae (SNe) can be used to measure H0, but this requires an external calibrator to convert relative distances to absolute ones. We use the angular diameter distance to strong gravitational lenses as a suitable calibrator, which is only weakly sensitive to cosmological assumptions. We determine the angular diameter distances to two gravitational lenses, 810−130+160 and 1230−150+180 megaparsec, at redshifts z=0.295 and 0.6304. Using these absolute distances to calibrate 740 previously measured relative distances to SNe, we measure the Hubble constant to be H0=82.4−8.3+8.4 kilometers per second per megaparsec.

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