scholarly journals Local burst model of CMB temperature fluctuations: luminescence in lines of primary para- and orthohelium

2018 ◽  
Vol 619 ◽  
pp. A29 ◽  
Author(s):  
V. Dubrovich ◽  
S. Grachev ◽  
T. Zalialiutdinov

We have considered the formation of the luminescent subordinate HeI lines by the absorption of continuum radiation from a source in the lines of the main HeI series in the expanding Universe. It is suggested that at some moment of time, corresponding to the redshift z0, a burst of superequilibrium blackbody radiation with a temperature T + ΔT occurs. This radiation is partially absorbed at different z <  z0 in the lines of the main HeI series and then converted into the radiation of subordinate lines. If νij is the laboratory frequency of the transition of some subordinate line originating at some z, then in the present time its frequency will be ν = νij/(1 + z). For different z (and, consequently, for different ν), the quantum yield for the subordinate lines of para- and orthohelium - the number of photons emitted in the subordinate line, per one initial excited atom and line profiles are calculated. Different pumping channels were considered. Spatial and angular distributions of radiation intensity of luminescent lines for the spherically symmetric radiation sources are presented. It is shown that for sufficiently large ΔT/T, the luminescent lines can be very noticeable in the spectrum of blackbody background radiation.

1985 ◽  
Vol 19 (1) ◽  
pp. 661-664
Author(s):  
D. T. Wilkinson ◽  
F. Melchiorri

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.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Koustav Konar ◽  
Kingshuk Bose ◽  
R. K. Paul

AbstractBlackbody radiation inversion is a mathematical process for the determination of probability distribution of temperature from measured radiated power spectrum. In this paper a simple and stable blackbody radiation inversion is achieved by using an analytical function with three determinable parameters for temperature distribution. This inversion technique is used to invert the blackbody radiation field of the cosmic microwave background, the remnant radiation of the hot big bang, to infer the temperature distribution of the generating medium. The salient features of this distribution are investigated and analysis of this distribution predicts the presence of distortion in the cosmic microwave background spectrum.


1988 ◽  
Vol 126 ◽  
pp. 691-692
Author(s):  
Herwig Dejonghe

A 1-parameter family of anisotropic models is presented. They all satisfy the Plummer law in the mass density, but have different velocity dispersions. Moreover, the stars are not confined to a particular subset of the total accessible phase space. This family is mathematically simple enough to be explored analytically in detail. The family is rich enough though to allow for a 3-parameter generalization which illustrates that even when both the mass density and the velocity dispersion profiles are required to be the same, a degeneracy in the possible distribution functions persists. The observational consequences of the degeneracy can be studied by calculating the observable radial velocity line profiles obtained with different distribution functions. It turns out that line profiles are relatively sensitive to changes in the distribution function. They therefore can be considered to be more natural observables when a determination of the distribution function is desired.


1990 ◽  
Vol 139 ◽  
pp. 402-403
Author(s):  
Bronislaw Rudak

The Nagoya-Berkeley experiment has revealed a substantial excess over the blackbody radiation in the submillimetre part of wavelengths. Its origin is unknown. The concept of high-redshift cosmological dust (e.g., Hayakawa et al., 1987), though not without problems, remains one of the simplest explanations. It is clear that other types of observations will be necessary to identify the source of the excess. Needless to say, searches for cosmic background radiation (CBR) intensity fluctuations on fine angular scales in the submillimetre region are especially desired.


2020 ◽  
Vol 492 (4) ◽  
pp. 5052-5056 ◽  
Author(s):  
V N Yershov ◽  
A A Raikov ◽  
N Yu Lovyagin ◽  
N P M Kuin ◽  
E A Popova

ABSTRACT It is possible to reduce the discrepancy between the local measurement of the cosmological parameter H0 and the value derived from the Planck measurements of the cosmic microwave background (CMB) by considering contamination of the CMB by emission from some medium around distant extragalactic sources, such as extremely cold coarse-grain dust. Though being distant, such a medium would still be in the foreground with respect to the CMB, and, as any other foreground, it would alter the CMB power spectrum. This could contribute to the dispersion of CMB temperature fluctuations. By generating a few random samples of CMB with different dispersions, we have checked that the increased dispersion leads to a smaller estimated value of H0, the rest of the cosmological model parameters remaining fixed. This might explain the reduced value of the Planck-derived parameter H0 with respect to the local measurements. The signature of the distant foreground in the CMB traced by supernovae (SNe) was previously reported by the authors of this paper – we found a correlation between the SN redshifts, zSN, and CMB temperature fluctuations at the SNe locations, TSN. Here we have used the slopes of the regression lines $T_{\rm SN}\, /\, z_{\rm SN}$ corresponding to different Planck wavebands in order to estimate the possible temperature of the distant extragalactic medium, which turns out to be very low, about 5 K. The most likely ingredient of this medium is coarse-grain (grey) dust, which is known to be almost undetectable, except for the effect of dimming remote extragalactic sources.


2010 ◽  
Vol 2010 (05) ◽  
pp. 033-033 ◽  
Author(s):  
Daisuke Yamauchi ◽  
Yuuiti Sendouda ◽  
Chul-Moon Yoo ◽  
Keitaro Takahashi ◽  
Atsushi Naruko ◽  
...  

2011 ◽  
Vol 190 ◽  
pp. 239-246
Author(s):  
Daisuke Yamauchi ◽  
Keitaro Takahashi ◽  
Yuuti Sendouda ◽  
Chul-Moon Yoo ◽  
Misao Sasaki

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