Cosmic microwave background

R. W. Wilson, The cosmic microwave background radiation, pp. 113-33 in I.es Prix Nobel 1978. Almqvist Wiksell International, Stockholm 1979. A. A. Penzias, The origin of the elements, pp. 93-106 in Les Prix Nobel 1978 (also in Science 105, 549-54 (1979)). 

A. A. Penzias and R. W- Wilson (Holm-del) discovery of cosmic microwave background radiation. 

The primordial Li abundance was sought primarily because of its ability to constrain the baryon to photon ratio in the Universe, or equivalently the baryon contribution to the critical density. In this way, Li was able to complement estimates from 4He, the primordial abundance of which varied only slightly with baryon density. Li also made up for the fact that the other primordial isotopes, 2H (i.e. D) and 3He, were at that time difficult to observe and/or interpret. During the late 1990 s, however, measurements of D in damped Lyman alpha systems (high column-density gas believed to be related to galaxy discs) provided more reliable constraints on the baryon density than Li could do (e.g. [19]). Even more recently, the baryon density has been inferred from the angular power spectrum of the cosmic microwave background radiation, for example from the WMAP measurements [26]. We consider the role of Li plateau observations post WMAP. 

The measurement of the cosmic microwave background. Far infrared astronomers were the first to develop thermal detectors. Some of the resulting technologies, such as neutron transmutation doping (NTD) [3], have been transferred to particle detection sensors and have allowed many groups (e.g., ref. [4-11] to make rapid progress). 

We shall now describe an infrared bolometer operating at 0.3 K, built by Lange et al. in 1992 [80], We chose this example because such composite bolometer can be easily described from a cryogenic point of view, whereas the analysis of more recent devices would be quite complicated. Nevertheless the bolometer performances are very good, the NEP being less than 10-16 W/(Hz)1/2 and the time constant r = 11ms. It was used for the measurement of the cosmic microwave background (CMB) in an experiment on board of a stratospheric balloon [81]. 

The main goal of the Planck instrument is to improve the accuracy of the measurement of the cosmic microwave background (CMB), in order to extract cosmological parameters that remain poorly constrained after the results of WMAP (Wilkinson microwave anisotropy probe) and of the best ground-based experiments. The basic idea of HFI-Planck is to use all the information contained in the CMB radiation, i.e. to perform a radiometric measurement limited by the quantum fluctuations of the CMB radiation itself. In these conditions, the accuracy is only limited by the number of detectors and by the duration of the observation. 

Black bodies emit radiation at all wavelengths. Using the spreadsheet, calculate the contribution to the visible spectrum from the cosmic microwave background in the visible region of the spectrum. 

Cosmic microwave background radiation Fossil radiation surviving form the Big Bang with a black body temperature of 2.725 K. 

The upper end of the range in t] is in excellent agreement with what has been deduced from WMAP measurements of the angular fluctuation spectrum of the cosmic microwave background (see Fig. 4.3 and Section 4.9). 

In consequence, the statistical characteristic temperature of relic radiation is fully determined in terms of relativistic invariant spectrum of the cosmic microwave background radiation and the distribution velocity function of radiating particles, i.e., is described with the following expression (compare with the results of reference (Einstein, 1965))... 

Like some other spectacular discoveries such as the cosmic microwave background, gamma-ray bursts (GRBs) were discovered by accident. Meant to monitor the outer space treaty , the American VELA satellites detected in July 1967 an intense flash of gamma-rays of unknown origin. It took until 1973 before the first detected GRBs were published for the scientific community (Klebesadel et al. 1973). 

Anisotropic effects of the recorded frequency of cosmic microwave background radiation have been proposed for photon rest mass determination [20]. 

With reference to Table I, the energy usually flows frum higher levels to luwer levels—in a direction such ihut the entropy increases. Thus, cosmic microwave background radiation is defined as the ultimate heai sink. i,e il represents the ultimate in energy degradation with no lower form in which to be convened. 

T. Villela, N. Figueiredo, and C. A. Wuensche, Photon Mass Inferred from Cosmic Microwave Background Radiation Maxwell s Equations in three-Dimensional Space, Instituto Nacional de Pesquisas Espaciais, Brazil, circa 1994, pp. 65-73. 

We give an estimation of the carbon fraction locked in these molecules. We discuss the rotation rates and electric dipole emission of hydrogenated icosahedral fullerenes in various phases of the interstellar medium. These molecules could be the carriers of the anomalous microwave emission detected by Watson et al. (Astrophys. J. 624 L89,2005) in the Perseus molecular complex and Cassasus et al. (2006) in the dark cloud LDN 1622. Hydrogenated forms of fullerenes may account for the dust-correlated microwave emission detected in our Galaxy by Cosmic Microwave Background experiments. 

Finally, hydrogenated fullerenes have been proposed as carriers of the anomalous microwave emission recently detected by several experiments on the Cosmic Microwave Background (Iglesias-Groth 2005, 2006). In the interstellar medium these molecules should spin with rates of several to tens of gigaHertz, if as expected they have a small dipole moment, then they would emit electric dipole radiation in a frequency range very similar to that observed for the anomalous microwave emission. 

Moreover, since the number of photons of the Universe is known now-a-days from the Cosmic Microwave Background ... 

The Cosmic Microwave Background (CMB) was first seen via its effect on the interstellar CN radical (Adams, 1941) but the significance of the this datum was not realized until after 1965 (Thaddeus, 1972 Kaiser and Wright, 1990). In fact, Herzberg, 1950 calculated a 2.3 K excitation temperature for the CN transition and said it had of course only a very restricted meaning. Later work by Roth et al., 1993 obtained a value for T0 = 2.729iJj Jjif i K at the CN 1-0 wavelength of 2.64 mm which is still remarkably accurate. 

Shortly after the Cosmic Microwave Background (CMB) was discovered, the first anisotropy in the CMB was seen the dipole pattern due to the motion of the observer relative to the rest of the Universe (Conklin, 1969). After confirmation by Henry, 1971 and by Corey and Wilkinson, 1976 the fourth discovery of the dipole (Smoot et al., 1977) showed a very definite cosine pattern as expected for a Doppler effect, and placed an upper limit on any further variations in Tcmb Further improvements in the measurement of the dipole anisotropy were made by the Differential Microwave Radiometers (DMR) experiment on COBE (Bennett et al., 1996 and by the Wilkinson Microwave... 

The Cosmic Microwave Background (as discussed, for example, in Ned Wright s contribution to this volume), is, along with the expansion of the Universe and the abundance of the light elements, one of the three so-called pil-... 

Kosowsky, A. 1999, New Astronomy Review, 43, 157 Kosowsky, A. 2002, The cosmic microwave background. In Modern Cosmology, 219. 

---