Calculation of Cosmic microwave background radiation parameters using COBE/FIRAS dataset

In this paper, we estimate the Cosmic Microwave Background (CMB) temperature using the data of the monopole spectrum from the Cosmic Background Explorer/ Far-Infrared Absolute Spectrophotometer (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 (2.725007 +/- 0.000024) K (only statistical error) by using the monopole spectrum. Handling the data of the monopole spectrum the chemical potential is obtained as (-1.1 +/- 3.4) x 10(-5) with an upper bound |mu| < 5.7 x 10(-5 )(95% confidence level). The amplitude of the CMB dipole is found to be, T-amp = (3.47 +/- 0.11) mK. We estimate an upper limit for the rms value of the fluctuation in chemical potential as Delta mu < 1.2 x 10(-4) (95% confidence level). The upper limit of y- distortion is calculated as y < 1.0 x 10(-4) (95% confidence level).