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 2. Anisotropy of the blackbody radiation

1985 ◽  
Vol 19 (1) ◽  
pp. 661-664
Author(s):  
D. T. Wilkinson ◽  
F. Melchiorri
Keyword(s):  
Background Radiation ◽  
Temperature Fluctuations ◽  
Thomson Scattering ◽  
Blackbody Radiation ◽  
Density Fluctuations ◽  
Microwave Background ◽  
Initial Temperature Distribution ◽  
Microwave Background Radiation ◽  
Expansion Of The Universe ◽  
The Universe

The 2.7 K microwave background radiation provides a sensitive probe of the universe in the interesting, but poorly understood, epoch around z ˜ 1000. At this time (age ~ 10 yr) the universe has cooled to T ~ 4000 K, the plasma combines, Thomson scattering ceases, and matter and blackbody radiation decouple. Subsequently, the radiation freely propagates to us, carrying the imprint of temperature fluctuations on the z ~ 1000 surface. The temperature fluctuations could have been caused by primordial density fluctuations, anisotropy in the expansion of the universe, or inhomogeneity in the initial temperature distribution; the z = 1000 surface we see was not causally connected at the time the radiation was released. Interpretation of the anisotropy measurements is complicated by the possibility that the matter may have been reionized (e.g. by massive stars), so the radiation may have been rescattered, possibly as late as z ~ 7.

scholarly journals Fluctuations of the Microwave Background Radiation

1978 ◽  
Vol 79 ◽  
pp. 393-404
Author(s):  
R. A. Sunyaev
Keyword(s):  
Large Scale ◽  
Background Radiation ◽  
Small Scale ◽  
Clusters Of Galaxies ◽  
Microwave Background ◽  
X Ray ◽  
M 10 ◽  
Microwave Background Radiation ◽  
Density Perturbations ◽  
The Universe

Investigations of small scale angular fluctuations and the spectrum of the microwave background radiation is one of the main methods of studying the large scale structure of the Universe. Figure 1 shows the principal stages of the evolution of the Universe. Today we can directly observe galaxies, clusters of galaxies and quasars in the redshift range z ≤ 3.5 by optical, radio and X-ray astronomy. These observations show that significant density perturbations δρ/ρ > 1 are present on mass scales M < 1016 M⊙. the Universe is essentially uniform δρ/ρ < 1 on large scales M ≫ 1016 M⊙.

OBSERVATIONAL COSMOLOGY 2004: WHAT THE DATA SAY ABOUT DARK ENERGY AND THE CONTENTS OF THE UNIVERSE

2005 ◽  
Vol 20 (14) ◽  
pp. 2931-2942
Author(s):  
JOSEPH FOWLER
Keyword(s):  
Dark Energy ◽  
Background Radiation ◽  
Current Data ◽  
Observational Cosmology ◽  
Microwave Background ◽  
Hubble Expansion ◽  
Microwave Background Radiation ◽  
Expansion Of The Universe ◽  
Cosmological Data ◽  
The Universe

The latest cosmological data point to a model of the universe that is self-consistent but deeply weird. It seems that most matter in our universe is non-baryonic and hidden from direct view. Meanwhile, a repulsive "dark energy" causes the expansion of the universe to proceed at an accelerating rate. Sources of current data include studies of the distribution of matter in the universe, the anisotropies of the cosmic microwave background radiation, and the Hubble expansion law as probed by distant supernovae. In the near future, we can hope that measurements like these will begin to illuminate the nature of dark energy, starting with the question of whether it behaves like a cosmological constant or shows a more complicated evolution.

scholarly journals DIVISION VIII: GALAXIES AND THE UNIVERSE

2008 ◽  
Vol 4 (T27A) ◽  
pp. 283-285
Author(s):  
Sadanori Okamura ◽  
Elaine Sadler ◽  
Francesco Bertola ◽  
Mark Birkinshaw ◽  
Françoise Combes ◽  
...  
Keyword(s):  
Computer Simulations ◽  
Large Scale ◽  
Background Radiation ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Clusters Of Galaxies ◽  
Microwave Background ◽  
Wide Range ◽  
Microwave Background Radiation ◽  
The Universe

Division VIII provides a focus for astronomers studying a wide range of problems related to galaxies and cosmology. Objects of the study include individual galaxies, groups and clusters of galaxies, large scale structure, comic microwave background radiation and the universe itself. Approaches are diverse from observational one to theoretical one including computer simulations.

scholarly journals Dragging Force on Galaxies Due to Streaming Dark Matter

1990 ◽  
Vol 124 ◽  
pp. 645-649
Author(s):  
Tetsuya Hara ◽  
Shigeru Miyoshi
Keyword(s):  
Dark Matter ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Rest Frame ◽  
Background Radiation ◽  
Clusters Of Galaxies ◽  
Microwave Background ◽  
The Galaxy ◽  
Microwave Background Radiation ◽  
The Universe

It has been reported that galaxies in large regions (~102Mpc), including some clusters of galaxies, may be streaming coherently with velocities up to 600km/sec or more with respect to the rest frame determined by the microwave background radiation.) On the other hand, it is suggested that the dominant mass component of the universe is dark matter. Because we can only speculate the motion of dark matter from the galaxy motions, much attention should be paid to the correlation of velocities between the observed galaxies and cold dark matter. So we investigate whether such coherent large-scale streaming velocities are due to dark matter or only to baryonic objects which may be formed by piling up of gases due to some explosive events.

scholarly journals R2 Gravity and the Structure of the Universe

1983 ◽  
Vol 104 ◽  
pp. 483-484
Author(s):  
Kenneth Brecher
Keyword(s):  
Background Radiation ◽  
Big Bang ◽  
Microwave Background ◽  
The Standard Model ◽  
Microwave Background Radiation ◽  
Expansion Of The Universe ◽  
High Degree ◽  
Cosmological Constants ◽  
The Universe ◽  
Fundamental Physical

The “standard” hot big bang model accounts for the expansion of the Universe, the existence of the microwave background radiation, and the mass fraction of the light elements up to 4He. It does not account for the high degree of isotropy and homogeneity of the Universe in the large, nor of the existence of structure (galaxies, clusters) on smaller scales. Other problems, such as the lepton to baryon ratio, the preponderance of matter over antimatter, and the “coincidences” of dimensionless ratios of several fundamental physical and cosmological “constants” also lie outside of the “standard” model at present.

scholarly journals On Friedman equation, quadratic laws and the geometry of our universe

2021 ◽  
Vol 4 (1) ◽  
pp. 048-050
Author(s):  
Kalimuthu S
Keyword(s):  
General Relativity ◽  
Background Radiation ◽  
Wilkinson Microwave Anisotropy Probe ◽  
Relativistic Jets ◽  
Microwave Background ◽  
Quadratic Equations ◽  
Microwave Background Radiation ◽  
Radio Signals ◽  
Expansion Of The Universe ◽  
The Universe

Einstein’s special and general relativity revolutionized physics. The predictions of general relativity are Strong Lensing, Weak Lensing, Microlensing, Black Holes, Relativistic Jets, A Gravitational Vortex, Gravitational Waves, The Sun Delaying Radio Signals, Proof from Orbiting Earth, Expansion of the universe. The density of the universe determines the geometry and fate of the universe. According to Freedman’s equations of general relativity published in 1922 and 1924, the geometry of the universe may be closed, open and flat. It all depends upon the curvature of the universe also. Various results of Cosmic Microwave Background Radiation (CMBR), NASA’s Wilkinson Microwave Anisotropy Probe (WMAP), and ESA’s Planck spacecraft probes found that our universe is flat within a margin of 0.4% error. In this short work, by applying the laws of quadratic equations, we attempt to show that OUR UNIVERSE IS FLAT.

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.

scholarly journals PROBING THE ANISOTROPIC EXPANSION HISTORY OF THE UNIVERSE WITH COSMIC MICROWAVE BACKGROUND

2012 ◽  
Vol 27 (24) ◽  
pp. 1250144 ◽  
Author(s):  
RANJITA K. MOHAPATRA ◽  
P. S. SAUMIA ◽  
AJIT M. SRIVASTAVA
Keyword(s):  
Cosmic Microwave Background ◽  
Background Radiation ◽  
Microwave Background ◽  
Anisotropic Expansion ◽  
Microwave Background Radiation ◽  
Expansion Stage ◽  
History Of ◽  
Density Perturbations ◽  
Expansion Of The Universe ◽  
The Universe

We propose a simple technique to detect any anisotropic expansion stage in the history of the universe starting from the inflationary stage to the surface of last scattering from the cosmic microwave background radiation (CMBR) data. We use the property that any anisotropic expansion in the universe would deform the shapes of the primordial density perturbations and this deformation can be detected in a shape analysis of superhorizon fluctuations in CMBR. Using this analysis we obtain the constraint on any previous anisotropic expansion of the universe to be less than about 35%.

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