Distortion of Cosmic Microwave Background Radiation and Decay of Weakly Interacting Particles

Author(s):  
Katsuhiko Sato ◽  
Masahiro Kawasaki
1988 ◽  
Vol 130 ◽  
pp. 509-509
Author(s):  
Katsuhiko Sato ◽  
Masahiro Kawasaki

Recently Nagoya-Berkeley group (Matsumoto et al, 1987) observed microwave radiation in the Wien region precisely and found the excess of temperature. In the previous paper (kawasaki and Sato, 1986), we investigated the distortion of the spectrum of microwave background radiation due to the radiative decay of weakly interacting massive particles. At that time, however, the distortion was not observed. In the present paper, we investigated in detail whether the decay of WIMPs can account for the observed distortion of the spectrum or not. In Fig. 1, an example is shown.


1997 ◽  
Vol 06 (05) ◽  
pp. 535-544
Author(s):  
Petri Mähönen ◽  
Tetsuya Hara ◽  
Toivo Voll ◽  
Shigeru Miyoshi

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.


1998 ◽  
Vol 15 (1) ◽  
pp. 111-117 ◽  
Author(s):  
David Valls–Gabaud

AbstractWe briefly review three main applications of Hα surveys in cosmology, namely: (1) the diffuse Hα emission as a tracer of the free–free foreground that contaminates the fluctuations in the cosmic microwave background radiation; (2) the Hα emission from galaxies as a measure of the formation rate of massive stars, both at low and high redshift; and (3) the diffuse Hα emission from ionised clouds as a constraint on the local ionising background radiation.


Sign in / Sign up

Export Citation Format

Share Document