Some critiques of the big bang cosmology

Pecker, Jean‐Claude

doi:10.1007/bf02709322

Cited by 20 publications

(21 citation statements)

References 12 publications

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“…Sweeping dust out by the stellar radiation pressure is considered as an alternative mechanism in the literature. For the first time, this idea was expressed several decades ago [31][32][33]; and the sweeping of dust out of a disc galaxy has been simulated more than once [34][35][36][37][38]. The authors of those studies usually come to con-clusion that the sweeping-out of dust by the stellar radiation pressure is typical of most disc galaxies and may result in the observed emerging of extraplanar dust, which is accompanied by ejecting a substantial amount of heavy elements from galactic discs.…”

Section: Introductionmentioning

confidence: 99%

The Sweeping-out of Dust by Radiation Pressure of Stars and Chemical Composition Peculiarities of Disc Galaxies

2021

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Abstract— We consider the drift of dust grains of various sizes and chemical compositions caused by the stellar radiation pressure in the vicinity of the Milky Way. When integrating the equations of motion, in addition to the radiation pressure, we consider the gravitational attraction from various components of the Galaxy and the gas drag. It has been shown that carbonaceous grains of medium sizes (~0.01 μm) are swept out of the galactic disc most effectively. Smaller dust grains are swept out to a substantially lesser extent, or they are not swept out at all. We also consider the motion of silicate dust grains, including those with porous structure. It has been shown that silicate grains experience a considerably weaker impact of the radiation pressure. The simulation result of their motion does not essentially depend on whether their porosity is accounted for or ignored. The total rate of the Galaxy’s dust loss has turned out to be high—approximately 0.03 M⊙ per year, which is comparable to the effect produced by the other mechanisms ejecting heavy elements to the circumgalactic space. We discuss the potential of the sweeping of dust out of the Galaxy in formation of the radial metallicity gradient, as well as the prospects of detecting extensive dust structures in elliptical galaxies.

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Section: Introductionmentioning

confidence: 99%

The Sweeping-out of Dust by Radiation Pressure of Stars and Chemical Composition Peculiarities of Disc Galaxies

2021

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“…One can think of different roughness models representing the strong inhomogeneity of the TR, for instance with a different and very peculiar roughness model Pecker et al (1988) obtain an overestimation factor of more than 10 under some conditions. This means that our values of τ 0 may need to be decreased by a large factor due to a roughness effect.…”

Section: Roughness and Fine Structurementioning

confidence: 99%

Electron density in the quiet solar coronal transition region from SoHO/SUMER measurements of S VI line radiance and opacity

Buchlin¹,

Vial²

2009

A&A

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Context. The steep temperature and density gradients that are measured in the coronal transition region challenge the model interpretation of observations. Aims. We derive the average electron density n e in the region emitting the S vi lines. We use two different techniques, which allow us to derive linearly-weighted (opacity method) and quadratically-weighted (emission measure method) electron density along the line-of-sight, to estimate a filling factor or derive the layer thickness at the formation temperature of the lines.Methods. We analyze SoHO/SUMER spectroscopic observations of the S vi lines, using the center-to-limb variations in radiance, the center-to-limb ratios of radiance and line width, and the radiance ratio of the 93.3−94.4 nm doublet to derive the opacity. We also use the emission measure derived from radiance at disk center.Results. We derive an opacity τ 0 at S vi 93.3 nm line center of the order of 0.05. The resulting average electron density n e , under simple assumptions concerning the emitting layer, is 2.4 × 10 16 m −3 at T = 2 × 10 5 K. This value is higher than (and inconsistent with) the values obtained from radiance measurements (2 × 10 15 m −3 ). The last value corresponds to an electron pressure of 10 −2 Pa. Conversely, taking a classical value for the density leads to a too high value of the thickness of the emitting layer. Conclusions. The pressure derived from the emission measure method compares well with previous determinations. It implies a low opacity of between 5 × 10 −3 and 10 −2 . It remains unexplained why a direct derivation leads to a much higher opacity, despite tentative modeling of observational biases. Further measurements in S vi and other lines emitted at a similar temperature should be completed, and more realistic models of the transition region need to be used.

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“…Dust particles ejected from galaxies by radiation pressure can be one of the possible sources of metals in the IGM. This possibility was first discussed in [22] with a negative conclusion. Detailed study initiated in [23] showed instead that the galactic radiation field is sufficient enough to expell dust particles in a relatively short time ∼ 10 8 yr at high distances from the plane, practically into the intergalactic space.…”

Section: Radiation Pressurementioning

confidence: 99%

Metal enrichment of the intergalactic medium

Shchekinov

2002

Astronomical & Astrophysical Transactions

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Recent observations show the presence of metals in low-density Lyα forest absorbers at high redshift (z ∼ 3). It remains still far from being clearly understood what mechanisms spread metals over Mpc scales from the parent galaxies, whether metals are homogeneously distributed in the intergalactic medium (IGM), how metallicity of the IGM does evolve. These questions are brifely addressed in this review.

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Some critiques of the big bang cosmology

Cited by 20 publications

References 12 publications

The Sweeping-out of Dust by Radiation Pressure of Stars and Chemical Composition Peculiarities of Disc Galaxies

The Sweeping-out of Dust by Radiation Pressure of Stars and Chemical Composition Peculiarities of Disc Galaxies

Electron density in the quiet solar coronal transition region from SoHO/SUMER measurements of S VI line radiance and opacity

Metal enrichment of the intergalactic medium

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