COSMOLOGY WITH CLUSTERS OF GALAXIES

2005 ◽  
Vol 20 (06) ◽  
pp. 1121-1131
Author(s):  
M. DONAHUE
Keyword(s):  
Initial Density ◽  
Cosmological Parameters ◽  
Matter Density ◽  
Type Ia Supernovae ◽  
Clusters Of Galaxies ◽  
Microwave Background ◽  
Type Ia ◽  
Density Perturbations ◽  
The Mean ◽  
Ia Supernovae

Cluster observations provide unique and useful constraints on cosmological parameters. The contents of clusters and the rate of their formation are very sensitive to the mean matter density (ΩM and the normalization and shape of the spectrum of initial density perturbations near the size scale of ~8h-1 Mpc . Future and on-going cluster studies constrain ΩΛ (acceleration) and the equation of state of the "dark energy," particularly in conjunction with either constraints from the cosmic microwave background or Type Ia supernovae of white dwarfs.

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.

Cosmological Parameters as Measured by Type Ia Supernovae

1999 ◽  
pp. 328-333
Author(s):  
Bruno Leibundgut ◽  
Brian Schmidt ◽  
Jason Spyromilio ◽  
Mark Phillips
Keyword(s):  
Cosmological Parameters ◽  
Type Ia Supernovae ◽  
Type Ia ◽  
Ia Supernovae

scholarly journals COSMOLOGICAL IMPLICATIONS OF CONFORMAL FIELD THEORY

2011 ◽  
Vol 26 (12) ◽  
pp. 893-900 ◽  
Author(s):  
ROBERT K. NESBET
Keyword(s):  
Gravitational Theory ◽  
Type Ia Supernovae ◽  
Microwave Background ◽  
Conformal Field ◽  
Peak Structure ◽  
Cosmic Evolution ◽  
Type Ia ◽  
Dynamical Breaking ◽  
Ia Supernovae ◽  
Conformal Symmetries

Requiring all massless elementary fields to have conformal scaling symmetry removes the conflict between gravitational theory and the quantum theory of elementary particles and fields. Extending this postulate to the scalar field of the Higgs model, dynamical breaking of both gauge and conformal symmetries determines parameters for the interacting fields. In uniform isotropic geometry a modified Friedmann cosmic evolution equation is derived with nonvanishing cosmological constant. Parameters determined by numerical solution are consistent with empirical data for redshifts z ≤ z* = 1090, including luminosity distances for observed type Ia supernovae and peak structure ratios in the cosmic microwave background (CMB). The theory does not require dark matter.

scholarly journals First cosmology results using Type IA supernovae from the dark energy survey: effects of chromatic corrections to supernova photometry on measurements of cosmological parameters

2019 ◽  
Vol 485 (4) ◽  
pp. 5329-5344 ◽  
Author(s):  
J Lasker ◽  
R Kessler ◽  
D Scolnic ◽  
D Brout ◽  
D L Burke ◽  
...  
Keyword(s):  
Dark Energy ◽  
Cosmological Parameters ◽  
Critical Density ◽  
Transmission Function ◽  
Type Ia Supernovae ◽  
Distance Modulus ◽  
Dark Energy Survey ◽  
Type Ia ◽  
Ia Supernovae ◽  
Energy Survey

Abstract Calibration uncertainties have been the leading systematic uncertainty in recent analyses using Type Ia supernovae (SNe Ia) to measure cosmological parameters. To improve the calibration, we present the application of spectral energy distribution-dependent ‘chromatic corrections’ to the SN light-curve photometry from the Dark Energy Survey (DES). These corrections depend on the combined atmospheric and instrumental transmission function for each exposure, and they affect photometry at the 0.01 mag (1 per cent) level, comparable to systematic uncertainties in calibration and photometry. Fitting our combined DES and low-z SN Ia sample with baryon acoustic oscillation (BAO) and cosmic microwave background (CMB) priors for the cosmological parameters Ωm (the fraction of the critical density of the universe comprised of matter) and w (the dark energy equation of state parameter), we compare those parameters before and after applying the corrections. We find the change in w and Ωm due to not including chromatic corrections is −0.002 and 0.000, respectively, for the DES-SN3YR sample with BAO and CMB priors, consistent with a larger DES-SN3YR-like simulation, which has a w-change of 0.0005 with an uncertainty of 0.008 and an Ωm change of 0.000 with an uncertainty of 0.002. However, when considering samples on individual CCDs we find large redshift-dependent biases (∼0.02 in distance modulus) for SN distances.

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