scholarly journals Can galaxy clusters, type Ia supernovae, and the cosmic microwave background rule out a class of modified gravity theories?

2016 ◽  
Vol 94 (10) ◽  
Author(s):  
R. F. L. Holanda ◽  
S. H. Pereira
Keyword(s):  
Cosmic Microwave Background ◽  
Galaxy Clusters ◽  
Modified Gravity ◽  
Type Ia Supernovae ◽  
Microwave Background ◽  
Modified Gravity Theories ◽  
Type Ia ◽  
Gravity Theories ◽  
Ia Supernovae ◽  
Rule Out

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 Correcting for peculiar velocities of Type Ia supernovae in clusters of galaxies

2018 ◽  
Vol 615 ◽  
pp. A162 ◽  
Author(s):  
P.-F. Léget ◽  
M. V. Pruzhinskaya ◽  
A. Ciulli ◽  
E. Gangler ◽  
G. Aldering ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Virgo Cluster ◽  
Type Ia Supernovae ◽  
Hubble Diagram ◽  
Cosmological Redshift ◽  
Peculiar Velocity ◽  
Peculiar Velocities ◽  
Velocity Correction ◽  
Type Ia ◽  
Ia Supernovae

Context. Type Ia supernovae (SNe Ia) are widely used to measure the expansion of the Universe. To perform such measurements the luminosity and cosmological redshift (z) of the SNe Ia have to be determined. The uncertainty on z includes an unknown peculiar velocity, which can be very large for SNe Ia in the virialized cores of massive clusters. Aims. We determine which SNe Ia exploded in galaxy clusters using 145 SNe Ia from the Nearby Supernova Factory. We then study how the correction for peculiar velocities of host galaxies inside the clusters improves the Hubble residuals. Methods. We found 11 candidates for membership in clusters. We applied the biweight technique to estimate the redshift of a cluster. Then, we used the galaxy cluster redshift instead of the host galaxy redshift to construct the Hubble diagram. Results. For SNe Ia inside galaxy clusters, the dispersion around the Hubble diagram when peculiar velocities are taken into account is smaller compared with a case without peculiar velocity correction, which has a wRMS = 0.130 ± 0.038 mag instead of wRMS = 0.137 ± 0.036 mag. The significance of this improvement is 3.58σ. If we remove the very nearby Virgo cluster member SN2006X (z < 0.01) from the analysis, the significance decreases to 1.34σ. The peculiar velocity correction is found to be highest for the SNe Ia hosted by blue spiral galaxies. Those SNe Ia have high local specific star formation rates and smaller stellar masses, which is seemingly counter to what might be expected given the heavy concentration of old, massive elliptical galaxies in clusters. Conclusions. As expected, the Hubble residuals of SNe Ia associated with massive galaxy clusters improve when the cluster redshift is taken as the cosmological redshift of the supernova. This fact has to be taken into account in future cosmological analyses in order to achieve higher accuracy for cosmological redshift measurements. We provide an approach to do so.

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.

Sign in / Sign up

Export Citation Format

Share Document