scholarly journals Stochastic optimization methods for extracting cosmological parameters from cosmic microwave background radiation power spectra

1999 ◽  
Vol 61 (2) ◽  
Author(s):  
Steen Hannestad
Keyword(s):  
Cosmic Microwave Background ◽  
Stochastic Optimization ◽  
Background Radiation ◽  
Radiation Power ◽  
Cosmological Parameters ◽  
Power Spectra ◽  
Optimization Methods ◽  
Cosmic Microwave Background Radiation ◽  
Microwave Background ◽  
Microwave Background Radiation

scholarly journals Current Status of the Cosmic Microwave Background Radiation

1999 ◽  
Vol 183 ◽  
pp. 74-87
Author(s):  
R. B. Partridge
Keyword(s):  
Power Spectrum ◽  
Cosmic Microwave Background ◽  
Background Radiation ◽  
Cosmological Parameters ◽  
Theoretical Description ◽  
Cosmic Microwave Background Radiation ◽  
Current Status ◽  
Next Generation ◽  
Microwave Background ◽  
Microwave Background Radiation

My goal is to summarize our understanding of the cosmic microwave background radiation (CMBR) at this interesting moment after the detection of fluctuations in the background and before the next generation of satellite experiments. I begin by listing recent reviews and papers on the spectrum of the CMBR. I then sketch the current theoretical description of the power spectrum of fluctuations in the CMBR. Astronomical foregrounds and the nature of secondary fluctuations are treated next. Then I turn to observations, with special emphasis on the final results of the COBE–DMR experiment, on the growing evidence for ΔT/T = 2–3 × 10−5 fluctuations at degree scales, and on what they tell us about cosmological parameters.

scholarly journals Cosmology (Cosmologie)

1991 ◽  
Vol 21 (1) ◽  
pp. 561-580
Keyword(s):  
Cosmic Microwave Background ◽  
Large Scale ◽  
Background Radiation ◽  
Cosmological Parameters ◽  
Large Scale Structure ◽  
Cosmic Microwave Background Radiation ◽  
Scale Structure ◽  
Microwave Background ◽  
Structure And Motion ◽  
Microwave Background Radiation

The last three years have been very fruitful ones in cosmology research. Brilliant achievement on the spectrum and homogeneities of cosmic microwave background radiation by COBE satellite is an example. It is, however, obviously impossible to review achievements in all fields in the number of pages allocated to our commission. This report, as in past reports, consists of some details of only some selected topics. I invited six active colleagues to collaborate in the preparation of this report. The topics are 1) Large Scale Structure and Motion (A. Dekel), 2) Formation of Galaxies and Large Scale Structure (S. Shandarin), 3) Active Galactic Nuclei in Cosmology (P.A. Shaver), 4) Cosmic Microwave Background Radiation (R. B. Partridge), 5) Primordial Nucleosynthesis (H. Reeves) and 6)The Cosmological Parameters (V. Trimble). Unfortunately, review on Early Universe could not be included because of the limit of page number, though it was planned originally. Recent developments in this area would be seen in the proceedings of recent international conferences (for example, Nobel Symposium 79 on ”The Birth and Early Evolution of Our Universe” Graeftavallen, Sweden, June, 1990, ed. B.-S. Skagerstam, World Scientific)

Statistics of Cosmic Microwave Background Radiation with the Cosmic String Model

1997 ◽  
Vol 06 (05) ◽  
pp. 535-544
Author(s):  
Petri Mähönen ◽  
Tetsuya Hara ◽  
Toivo Voll ◽  
Shigeru Miyoshi
Keyword(s):  
Cosmic Microwave Background ◽  
Cosmic String ◽  
Large Scale ◽  
Background Radiation ◽  
Unit Length ◽  
Angular Size ◽  
Cosmic Microwave Background Radiation ◽  
Density Parameter ◽  
Microwave Background ◽  
Microwave Background Radiation

We have studied the cosmic microwave background radiation by simulating the cosmic string network induced anisotropies on the sky. The large-angular size simulations are based on the Kaiser–Stebbins effect calculated from full cosmic-string network simulation. The small-angular size simulations are done by Monte-Carlo simulation of perturbations from a time-discretized toy model. We use these results to find the normalization of μ, the string mass per unit length, and compare this result with one needed for large-scale structure formation. We show that the cosmic string scenario is in good agreement with COBE, SK94, and MSAM94 microwave background radiation experiments with reasonable string network parameters. The predicted rms-temperature fluctuations for SK94 and MSAM94 experiments are Δ T/T=1.57×10-5 and Δ T/T=1.62×10-5, respectively, when the string mass density parameter is chosen to be Gμ=1.4×10-6. The possibility of detecting non-Gaussian signals using the present day experiments is also discussed.

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