scholarly journals Determining the motion of the Solar system relative to the cosmic microwave background using Type Ia supernovae

2008 ◽  
Vol 387 (1) ◽  
pp. 371-376 ◽  
Author(s):  
Christopher Gordon ◽  
Kate Land ◽  
Anže Slosar
Keyword(s):  
Solar System ◽  
Cosmic Microwave Background ◽  
Type Ia Supernovae ◽  
Microwave Background ◽  
Type Ia ◽  
Ia Supernovae

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.

scholarly journals IMPROVED LIMITS ON PHOTON VELOCITY OSCILLATIONS

2002 ◽  
Vol 17 (38) ◽  
pp. 2491-2496 ◽  
Author(s):  
ALESSANDRO DE ANGELIS ◽  
REYNALD PAIN
Keyword(s):  
Cosmic Microwave Background ◽  
Cosmological Constant ◽  
Active Galactic Nuclei ◽  
Gamma Rays ◽  
Optical Spectrum ◽  
Galactic Nuclei ◽  
Type Ia Supernovae ◽  
Microwave Background ◽  
Type Ia ◽  
Ia Supernovae

The mixing of the photon with a hypothetical sterile paraphotonic state would have consequences on the cosmological propagation of photons. The absence of distortions in the optical spectrum of distant Type Ia supernovae allows to extend by two orders of magnitude the previous limit on the Lorentz-violating parameter δ associated to the photon–paraphoton transition, extracted from the absence of distortions in the spectrum of the cosmic microwave background. The new limit is consistent with the interpretation of the dimming of distant Type Ia supernovae as a consequence of a nonzero cosmological constant. Observations of gamma-rays from active galactic nuclei allow to further extend the limit on δ.

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.

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 Precise initial abundance of Niobium-92 in the Solar System and implications for p-process nucleosynthesis

2021 ◽  
Vol 118 (8) ◽  
pp. e2017750118
Author(s):  
Makiko K. Haba ◽  
Yi-Jen Lai ◽  
Jörn-Frederik Wotzlaw ◽  
Akira Yamaguchi ◽  
Maria Lugaro ◽  
...  
Keyword(s):  
Solar System ◽  
High Precision ◽  
Half Life ◽  
Parent Body ◽  
Type Ia Supernovae ◽  
Core Collapse ◽  
Early Solar System ◽  
Type Ia ◽  
Mineral Pair ◽  
Ia Supernovae

The niobium-92–zirconium-92 (92Nb–92Zr) decay system with a half-life of 37 Ma has great potential to date the evolution of planetary materials in the early Solar System. Moreover, the initial abundance of the p-process isotope 92Nb in the Solar System is important for quantifying the contribution of p-process nucleosynthesis in astrophysical models. Current estimates of the initial 92Nb/93Nb ratios have large uncertainties compromising the use of the 92Nb–92Zr cosmochronometer and leaving nucleosynthetic models poorly constrained. Here, the initial 92Nb abundance is determined to high precision by combining the 92Nb–92Zr systematics of cogenetic rutiles and zircons from mesosiderites with U–Pb dating of the same zircons. The mineral pair indicates that the 92Nb/93Nb ratio of the Solar System started with (1.66 ± 0.10) × 10−5, and their 92Zr/90Zr ratios can be explained by a three-stage Nb–Zr evolution on the mesosiderite parent body. Because of the improvement by a factor of 6 of the precision of the initial Solar System 92Nb/93Nb, we can show that the presence of 92Nb in the early Solar System provides further evidence that both type Ia supernovae and core-collapse supernovae contributed to the light p-process nuclei.

Sign in / Sign up

Export Citation Format

Share Document