The primordial generation of random shear motions and small-scale angular anisotropy in the microwave background radiation

1974 ◽  
Vol 194 ◽  
pp. 215 ◽  
Author(s):  
J. Silk
Keyword(s):  
Background Radiation ◽  
Small Scale ◽  
Microwave Background ◽  
Angular Anisotropy ◽  
Microwave Background Radiation

scholarly journals Small Scale Fluctuations in the Microwave Background Radiation Associated with the Formation of Galaxies

1977 ◽  
Vol 74 ◽  
pp. 327-334
Author(s):  
R. A. Sunyaev
Keyword(s):  
Spatial Distribution ◽  
Background Radiation ◽  
Gravitational Instability ◽  
Thomson Scattering ◽  
Small Scale ◽  
Clusters Of Galaxies ◽  
Microwave Background ◽  
Microwave Background Radiation ◽  
Expansion Of The Universe ◽  
The Universe

According to current ideas, massive extragalactic systems such as galaxies and clusters of galaxies formed as a result of the growth of small fluctuations in density and velocity which were present in the early stages of expansion of the Universe under the influence of gravitational instability. According to the hot model of the Universe at the epoch corresponding to a redshift z ≈ 1500, recombination of primaeval hydrogen took place and as a result the optical depth of the Universe to Thomson scattering decreased abruptly from about 1000 to 1 - the Universe became transparent. Therefore the observed angular distribution of the microwave background radiation (MWBR) contains information about inhomogeneities in its spatial distribution at a redshift z ∼ 1000. Silk (1968) was the first to note that this “photograph” of the Universe at the epoch of recombination must be enscribed with fluctuations associated with perturbations in the space density and velocity of motion of matter which will later lead to the formation of galaxies and clusters of galaxies.

scholarly journals New Limits to the Small Scale Fluctuations in the Cosmic Background Radiation

1983 ◽  
Vol 104 ◽  
pp. 125-126
Author(s):  
K. I. Kellermann ◽  
E. B. Fomalont ◽  
J. V. Wall
Keyword(s):  
Cosmic Microwave Background ◽  
Radio Source ◽  
Flux Density ◽  
Background Radiation ◽  
Cosmic Background Radiation ◽  
Small Region ◽  
Small Scale ◽  
Microwave Background ◽  
Cosmic Background ◽  
Microwave Background Radiation

The VLA has been used at 4.9 GHz to observe a small region of sky in order to extend the radio source count to low flux density (Fomalont et al., these proceedings) and to look for small scale fluctuations in the 2.7 K cosmic microwave background radiation.

scholarly journals Deep Radio Source Counts and Small Scale Fluctuations of the Microwave Background Radiation

1983 ◽  
Vol 104 ◽  
pp. 131-133
Author(s):  
L. Danese ◽  
G. de Zotti ◽  
N. Mandolesi
Keyword(s):  
Radio Source ◽  
Background Radiation ◽  
Areal Density ◽  
Small Scale ◽  
Microwave Background ◽  
Direct Evaluation ◽  
Luminosity Functions ◽  
Microwave Background Radiation ◽  
Model Independent ◽  
Image Position

Source counts which now extend to surface densities of ∼105 sources/sr make possible a direct evaluation of the radio source contribution to the small-scale fluctuations in the microwave background on scales larger than ∼10′, at wavelengths cm. Comprehensive radio spectral data permit a straightforward and largely model-independent extrapolation of the N(S) relation to shorter wavelengths. On the other hand, Peacock and Gull (1981, hereafter PG) have constructed a set of models which incorporate a wealth of additional data, such as local luminosity functions, luminosity/redshift distributions, luminosity-spectral index correlations; they can therefore be exploited to optimize the extrapolations both to higher frequencies and to fainter flux densities. Only one of these models, however, namely No. 4, is consistent with the recent P(D) results (Wall et al. 1982; Ledden et al. 1980) which provide information on the areal density of sources at s~1mJy; therefore, in the following we shall focus on it.

scholarly journals Constraints on the mean density of the Universe which follow from the theories of adiabatic and whirl perturbations

1978 ◽  
Vol 79 ◽  
pp. 404-405
Author(s):  
A. A. Kurskov ◽  
L. M. Ozernoy
Keyword(s):  
Large Scale ◽  
Background Radiation ◽  
Small Scale ◽  
Microwave Background ◽  
Scale Temperature ◽  
Microwave Background Radiation ◽  
Initial Spectrum ◽  
Density Perturbations ◽  
The Mean ◽  
The Universe

The aim of this communication is to investigate what constraints to the cosmological parameter Ω = 2qO can be obtained if one assumes that primaeval whirl motions or adiabatic density perturbations with an appropriate initial spectrum were responsible for the formation of large scale structure in the Universe. These constraints are readily obtained from the two conditions: (i) an upper limit to small scale temperature fluctuations of the microwave background radiation, and (ii) the requirement that the primaeval perturbations should be large enough in order to produce observed structures.

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