“2016年IOAA理论第3题-早期宇宙”的版本间的差异
（创建页面，内容为“==英文原题== '''(T3) Early Universe''' Cosmological models indicate that radiation energy density, 𝜌<sub>r</sub> , in the Universe is proportional to (1 +…”） |
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, of the radiation at redshift 𝑧<sub>e</sub> | , of the radiation at redshift 𝑧<sub>e</sub> | ||
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(T3.3) Estimate the typical photon energy, 𝐸<sub>ν</sub> | (T3.3) Estimate the typical photon energy, 𝐸<sub>ν</sub> | ||
(in eV), of the radiation as emitted at redshift 𝑧<sub>e</sub> | (in eV), of the radiation as emitted at redshift 𝑧<sub>e</sub> | ||
2019年9月11日 (三) 17:27的版本
英文原题
(T3) Early Universe
Cosmological models indicate that radiation energy density, 𝜌r , in the Universe is proportional to (1 + 𝑧) 4 , and the matter energy density, 𝜌m, is proportional to (1 + 𝑧) 3 , where 𝑧 is the redshift. The dimensionless density parameter, Ω, is given as Ω = 𝜌/𝜌c , where 𝜌c is the critical energy density of the Universe. In the present Universe, the density parameters corresponding to radiation and matter, are Ωr0 = 10−4 and Ωm0 = 0.3, respectively.
(T3.1) Calculate the redshift, 𝑧e , at which radiation and matter energy densities were equal.
(T3.2) Assuming that the radiation from the early Universe has a blackbody spectrum with a temperature of 2.732 K, estimate the temperature, 𝑇e , of the radiation at redshift 𝑧e .
(T3.3) Estimate the typical photon energy, 𝐸ν (in eV), of the radiation as emitted at redshift 𝑧e .
