%0 Generic %1 klimenko2021estimation %A Klimenko, V. V. %A Ivanchik, A. V. %A Petitjean, P. %A Noterdaeme, P. %A Srianand, R. %D 2021 %K library %R 10.1134/S1063773720110031 %T Estimation of the CMB temperature from atomic C\,i and molecular CO lines in the interstellar medium of early galaxies %U http://arxiv.org/abs/2106.00119 %X The linear increase of the cosmic microwave background (CMB) temperature with cosmological redshift, $T_CMB = T_0(1 + z)$, is a prediction of the standard cosmological $Łambda$CDM model. There are currently two methods to measure this dependence at redshift $z>0$, and that is equally important to estimate the CMB temperature $T_0$ at the present epoch $z=0$. The first method is based on the Sunyaev-Zeldovich (SZ) effect for a galaxy cluster. aThe second method is based on the analysis of the populations of atomic and molecular energy levels observed in the absorption spectra of quasars. This method allows $T_CMB(z)$ to be measured directly. We present new estimates of $T_\rm CMB(z_i)$ in the redshift range $1.7z_i łe3.3$ based on the analysis of excitation of the CO rotational levels and C\,i fine-structure levels in 15 absorption systems. We take into account collisional excitation of CO and C\,i with hydrogen atoms and H$_2$ and radiative pumping of C\,i by the interstellar ultraviolet radiation. Applying this corrections leads to a systematic decrease in the previously obtained estimates of $T_CMB(z_i)$ (for some systems the magnitude of the effect is $\sim$10\%). Combining our measurements with the measurements of $T_CMB(z)$ in galaxy clusters we have obtained a constraint on the parameter $\beta=+0.010\pm0.013$, which characterizes the deviation of the CMB temperature from the standard relation, $T_CMB = T_0(1 + z)^1-\beta$, and an independent estimate of the CMB temperature at the present epoch, $T_0 = 2.719\pm0.009$\,K, which agrees well with the estimate from orbital measurements, $T_0 = 2.7255\pm0.0006$\,K. This independent estimate is very important because it was obtained using cosmological data, in contrast to satellite measurements, which are obtained "here" and "now".

@misc{klimenko2021estimation, abstract = {The linear increase of the cosmic microwave background (CMB) temperature with cosmological redshift, $T_{\rm CMB} = T_0(1 + z)$, is a prediction of the standard cosmological $\Lambda$CDM model. There are currently two methods to measure this dependence at redshift $z>0$, and that is equally important to estimate the CMB temperature $T_0$ at the present epoch $z=0$. The first method is based on the Sunyaev-Zeldovich (SZ) effect for a galaxy cluster. aThe second method is based on the analysis of the populations of atomic and molecular energy levels observed in the absorption spectra of quasars. This method allows $T_{\rm CMB}(z)$ to be measured directly. We present new estimates of $T_{\rm CMB}(z_i)$ in the redshift range $1.7\le z_i \le3.3$ based on the analysis of excitation of the CO rotational levels and C\,{\sc i} fine-structure levels in 15 absorption systems. We take into account collisional excitation of CO and C\,{\sc i} with hydrogen atoms and H$_2$ and radiative pumping of C\,{\sc i} by the interstellar ultraviolet radiation. Applying this corrections leads to a systematic decrease in the previously obtained estimates of $T_{\rm CMB}(z_i)$ (for some systems the magnitude of the effect is $\sim$10\%). Combining our measurements with the measurements of $T_{\rm CMB}(z)$ in galaxy clusters we have obtained a constraint on the parameter $\beta=+0.010\pm0.013$, which characterizes the deviation of the CMB temperature from the standard relation, $T_{\rm CMB} = T_0(1 + z)^{1-\beta}$, and an independent estimate of the CMB temperature at the present epoch, $T_0 = 2.719\pm0.009$\,K, which agrees well with the estimate from orbital measurements, $T_0 = 2.7255\pm0.0006$\,K. This independent estimate is very important because it was obtained using cosmological data, in contrast to satellite measurements, which are obtained "here" and "now".}, added-at = {2021-06-02T05:49:52.000+0200}, author = {Klimenko, V. V. and Ivanchik, A. V. and Petitjean, P. and Noterdaeme, P. and Srianand, R.}, biburl = {https://www.bibsonomy.org/bibtex/261b28c09a6d0b33dd13c454ac5688eb1/gpkulkarni}, description = {Estimation of the CMB temperature from atomic C\,{\sc i} and molecular CO lines in the interstellar medium of early galaxies}, doi = {10.1134/S1063773720110031}, interhash = {82a777a116da4542b39cf4e19e3ca20b}, intrahash = {61b28c09a6d0b33dd13c454ac5688eb1}, keywords = {library}, note = {cite arxiv:2106.00119Comment: 8 pages, 4 figures, 5 tables}, timestamp = {2021-06-02T05:49:52.000+0200}, title = {Estimation of the CMB temperature from atomic C\,{\sc i} and molecular CO lines in the interstellar medium of early galaxies}, url = {http://arxiv.org/abs/2106.00119}, year = 2021 }