The Astrophysical Journal · 1996 · 1.6K citations · 9 references
FIRAS measures the difference between the cosmic microwave background and a precise blackbody spectrum. The authors refined the analysis of FIRAS data from the COBE mission. The refined analysis yields tighter upper limits on deviations from a blackbody spectrum, with rms deviations below 50 ppm, |y| < 15 × 10⁻⁶, |μ| < 9 × 10⁻⁵, and updated values for the CMB temperature (2.728 ± 0.004 K), dipole direction, and amplitude, all consistent with prior results.
We have refined the analysis of the data from the FIRAS (Far-InfraRed Absolute Spectrophotometer) on board the COBE (COsmic Background Explorer). The FIRAS measures the difference between the cosmic microwave background and a precise blackbody spectrum. We find new, tighter upper limits on general deviations from a blackbody spectrum. The rms deviations are less than 50 parts per million of the peak of the cosmic microwave background radiation. For the Comptonization and chemical potential, we find |y| < 15 × 10–6 and |μ| < 9 × 10–5 (95% confidence level [CL]). There are also refinements in the absolute temperature, 2.728 ± 0.004 K (95% CL), the dipole direction, (1, b)/(26414 ± 0.30, 4826 ± 0.30) (95% CL), and the amplitude, 3.372 ± 0.014 mK (95% CL). All of these results agree with our previous publications.
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Cosmic microwave background dipole spectrum measured by the COBE FIRAS instrument
D. J. Fixsen, E. S. Cheng, D. A. Cottingham et al. · The Astrophysical Journal · 1994 · 106 citations
Distortions of the Background Radiation Spectrum
R. A. Sunyaev, Ya. B. Zel’dovich · Nature · 1969 · 73 citations