Small-scale fluctuations in the microwave background radiation and multiple gravitational lensing

1988 ◽  
Vol 331 ◽  
pp. L1 ◽  
Author(s):  
A. Kashlinsky
Keyword(s):  
Gravitational Lensing ◽  
Background Radiation ◽  
Small Scale ◽  
Microwave Background ◽  
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 Astronomical Signatures of Dark Matter

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Paul Gorenstein ◽  
Wallace Tucker
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Background Radiation ◽  
Electromagnetic Spectrum ◽  
Clusters Of Galaxies ◽  
Microwave Background ◽  
Solar Mass ◽  
Rotation Rates ◽  
Microwave Background Radiation ◽  
Unambiguous Detection

Several independent astronomical observations in different wavelength bands reveal the existence of much larger quantities of matter than what we would deduce from assuming a solar mass to light ratio. They are very high velocities of individual galaxies within clusters of galaxies, higher than expected rotation rates of stars in the outer regions of galaxies, 21 cm line studies indicative of increasing mass to light ratios with radius in the halos of spiral galaxies, hot gaseous X-ray emitting halos around many elliptical galaxies, and clusters of galaxies requiring a much larger component of unseen mass for the hot gas to be bound. The level of gravitational attraction needed for the spatial distribution of galaxies to evolve from the small perturbations implied by the very slightly anisotropic cosmic microwave background radiation to its current web-like configuration requires much more mass than is observed across the entire electromagnetic spectrum. Distorted shapes of galaxies and other features created by gravitational lensing in the images of many astronomical objects require an amount of dark matter consistent with other estimates. The unambiguous detection of dark matter and more recently evidence for dark energy has positioned astronomy at the frontier of fundamental physics as it was in the 17th century.

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