Cosmological Constraints from Current Cosmic Microwave Background and Type Ia Supernova Data: A Brute Force, Eight-Parameter Analysis

1999 ◽  
Vol 514 (2) ◽  
pp. L69-L72 ◽  
Author(s):  
Max Tegmark
Keyword(s):  
Cosmic Microwave Background ◽  
Parameter Analysis ◽  
Brute Force ◽  
Microwave Background ◽  
Cosmological Constraints ◽  
Type Ia Supernova ◽  
Type Ia

Cosmological constraints on the variable modified Chaplygin gas model by using MCMC approach

2015 ◽  
Vol 24 (08) ◽  
pp. 1550059 ◽  
Author(s):  
Jian-bin Chen ◽  
Zhen-qi Liu ◽  
Lili Xing
Keyword(s):  
Apparent Horizon ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Acoustic Oscillations ◽  
Microwave Background ◽  
Mean Values ◽  
Cosmological Constraints ◽  
Variable Modified Chaplygin Gas ◽  
Type Ia ◽  
Ia Supernovae

We investigate the cosmological constraints on the variable modified Chaplygin gas (VMCG) model from the latest observational data: Union2 dataset of Type Ia supernovae (SNIa), the observational Hubble data (OHD), the baryon acoustic oscillations (BAO) and the cosmic microwave background (CMB) data. By using the Markov chain Monte Carlo (MCMC) method, we obtain the mean values of parameters in the flat model: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]. Furthermore, we investigate the thermodynamical properties of VMCG model at apparent horizon, event horizon and particle horizon respectively.

scholarly journals Cosmology from large-scale structure

2020 ◽  
Vol 633 ◽  
pp. L10 ◽  
Author(s):  
Tilman Tröster ◽  
Ariel. G. Sánchez ◽  
Marika Asgari ◽  
Chris Blake ◽  
Martín Crocce ◽  
...  
Keyword(s):  
Cosmic Microwave Background ◽  
Parameter Space ◽  
Large Scale ◽  
Bayes Factor ◽  
Large Scale Structure ◽  
Data Sets ◽  
Microwave Background ◽  
Shape Information ◽  
Galaxy Clustering ◽  
Cosmological Constraints

We reanalyse the anisotropic galaxy clustering measurement from the Baryon Oscillation Spectroscopic Survey (BOSS), demonstrating that using the full shape information provides cosmological constraints that are comparable to other low-redshift probes. We find Ωm = 0.317+0.015−0.019, σ8 = 0.710±0.049, and h = 0.704 ± 0.024 for flat ΛCDM cosmologies using uninformative priors on Ωch2, 100θMC, ln1010As, and ns, and a prior on Ωbh2 that is much wider than current constraints. We quantify the agreement between the Planck 2018 constraints from the cosmic microwave background and BOSS, finding the two data sets to be consistent within a flat ΛCDM cosmology using the Bayes factor as well as the prior-insensitive suspiciousness statistic. Combining two low-redshift probes, we jointly analyse the clustering of BOSS galaxies with weak lensing measurements from the Kilo-Degree Survey (KV450). The combination of BOSS and KV450 improves the measurement by up to 45%, constraining σ8 = 0.702 ± 0.029 and S8 = σ8 Ωm/0.3 = 0.728 ± 0.026. Over the full 5D parameter space, the odds in favour of a single cosmology describing galaxy clustering, lensing, and the cosmic microwave background are 7 ± 2. The suspiciousness statistic signals a 2.1 ± 0.3σ tension between the combined low-redshift probes and measurements from the cosmic microwave background.

COSMIC CONSTRAINTS ON DECELERATION PARAMETER WITH Sne Ia AND CMB

2009 ◽  
Vol 24 (05) ◽  
pp. 369-376 ◽  
Author(s):  
LIXIN XU ◽  
JIANBO LU
Keyword(s):  
Cosmic Microwave Background ◽  
Observational Data ◽  
Deceleration Parameter ◽  
Background Radiation ◽  
Cosmic Microwave Background Radiation ◽  
Accelerated Expansion ◽  
Microwave Background ◽  
Strong Constraint ◽  
Microwave Background Radiation ◽  
Type Ia

In this paper, a parametrized deceleration parameter q(a) = q0+q1(1-a) is constrained by using the current cosmic observational data from type Ia Supernova (Sne Ia) and Cosmic Microwave Background Radiation (CMB). When the CMB dataset is added as a strong constraint, it is found that the 1σ error is largely reduced. The values of transition redshift zT from decelerated expansion to accelerated expansion and current deceleration parameter q0 are larger than that obtained from the case where Sne Ia dataset is used alone. With comparison to the case of Sne Ia 182 dataset used,15 it is found that the value of transition redshift is smaller than that in Sne 192 dataset case. This is the so-called dataset dependence.

scholarly journals Can f(R) gravity relieve $$H_0$$ and $$\sigma _8$$ tensions?

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Deng Wang
Keyword(s):  
Cosmic Microwave Background ◽  
Confidence Level ◽  
Cosmological Parameters ◽  
Type Ia Supernovae ◽  
Acoustic Oscillations ◽  
Microwave Background ◽  
Type Ia ◽  
Baryon Acoustic Oscillations ◽  
Ia Supernovae

AbstractTo investigate whether f(R) gravity can relieve current $$H_0$$ H 0 and $$\sigma _8$$ σ 8 tensions, we constrain the Hu-Sawicki f(R) gravity with Planck-2018 cosmic microwave background and redshift space distortions observations. We find that this model fails to relieve both $$H_0$$ H 0 and $$\sigma _8$$ σ 8 tensions, and that its two typical parameters $$\log _{10}f_{R0}$$ log 10 f R 0 and n are insensitive to other cosmological parameters. Combining the cosmic microwave background, baryon acoustic oscillations, Type Ia supernovae, cosmic chronometers with redshift space distortions observations, we give our best constraint $$\log _{10}f_{R0}<-6.75$$ log 10 f R 0 < - 6.75 at the $$2\sigma $$ 2 σ confidence level.

Sign in / Sign up

Export Citation Format

Share Document