Reanalysing cosmic microwave background radiation using a straight-line fit approach

In this paper, we estimate the cosmic microwave background (CMB) temperature using the data of the monopole spectrum and the dipole spectrum from COBE/FIRAS. Utilising the idea of straight-line fitting, we obtain the temperature and chemical potential. The temperature of the CMB is found to be \({2.728\pm 2.681\times 10}^{-5}\) K and \(2.728\pm 2.779\times {10}^{-5}\) K by using the data of the monopole and the dipole spectrum respectively. Handling the data of the monopole and the dipole spectrum, the chemical potential is obtained as \(4.858\times {10}^{-4}\pm 3.681\times {10}^{-5}\) and \(5.044\times {10}^{-4}\pm 3.762\times {10}^{-5}\) (95% confidence level) respectively. The amplitude of the CMB dipole, \({\text{T}}_{\text{a}\text{m}\text{p} }=3.387\pm 0.044\) mK is obtained at\(2.178\times {10}^{11}\)Hz. We get the fluctuation in chemical potential as \(\pm 4.945\times {10}^{-5}\) and \(\pm 5.126\times {10}^{-5}\) considering the variation in temperature by using the data of monopole and dipole spectrum respectively. While analysing the y-distortion we get a peak in the value of y at \(2.178\times {10}^{11}\)Hz and |y| = \(6.063\times {10}^{-5}\) excluding the peak.