نتایج جستجو برای: cosmic expansion

تعداد نتایج: 171725  

Journal: :Monthly Notices of the Royal Astronomical Society 2021

ABSTRACT The cosmological constant ? is usually interpreted as Dark Energy (DE) or modified gravity (MG). Here, we propose instead that corresponds to a boundary term in the action of classical General Relativity. zero for perfect fluid solution and this fixes average density ? pressure p inside primordial causal boundary: = 4?G <?+3p >. This explains both why observed value relat...

2004
Birgit Eberle Andreas Ringwald Liguo Song Thomas J. Weiler

Resonant annihilation of extremely high-energy cosmic neutrinos on big-bang relic anti-neutrinos (and vice versa) into Z-bosons leads to sizable absorption dips in the neutrino flux to be observed at Earth. The high-energy edges of these dips are fixed, via the resonance energies, by the neutrino masses alone. Their depths are determined by the cosmic neutrino background density, by the cosmolo...

1999
K. M. Górski

We propose a formalism for estimating the skewness and angular power spectrum of a general Cosmic Microwave Background data set. We use the Edgeworth Expansion to define a non-Gaussian likelihood function that takes into account the anisotropic nature of the noise and the incompleteness of the sky coverage. The formalism is then applied to estimate the skewness of the publicly available 4 year ...

2015
Bridget Falck Kazuya Koyama Gong-Bo Zhao

Theories which modify general relativity to explain the accelerated expansion of the Universe often use screening mechanisms to satisfy constraints on Solar System scales. We investigate the effects of the cosmic web and the local environmental density of dark matter halos on the screening properties of the Vainshtein and chameleon screening mechanisms. We compare the cosmic web morphology of d...

1999
C. R. Contaldi P. G. Ferreira J. Magueijo K. M. Górski

We propose a formalism for estimating the skewness and angular power spectrum of a general Cosmic Microwave Background data set. We use the Edgeworth Expansion to define a non-Gaussian likelihood function that takes into account the anisotropic nature of the noise and the incompleteness of the sky coverage. The formalism is then applied to estimate the skewness of the publicly available 4 year ...

2008
E. A. Dorfi H. J. Völk

Spherically symmetric numerical models of supernova remnants (SNRs) evolving from the initial explosion up to their final dispersal within the interstellar medium (ISM) and exploding into a tenuous and hot plasma are presented. The parameters of the exploding stars are typical for an old stellar population (Type I SNe) and the external medium is characterized by a temperature between 106K and 3...

2008
Luis O. Pimentel César Mora

We study the third quantization of a Brans-Dicke toy model, we calculate the number density of the universes created from nothing and found that it has a Planckian form. Also, we calculated the uncertainty relation for this model by means of functional Schrödinger equation and we found that fluctuations of the third-quantized universe field tends to a finite limit in the course of cosmic expans...

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