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arXiv · 2411.03056

Constraining $\mu$ and $y$ distortions in the Cosmic Microwave Background with COBE/FIRAS Data

Somita Dhal·Koustav Konar·R. K. Paul
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Abstract

This paper presents a novel approach to constrain the $\mu$- and y- distortions in the Cosmic Microwave Background (CMB) using the COBE/FIRAS data. The analysis draws from the concept of blackbody radiation inversion (BRI), a mathematical technique typically used to determine the temperature distribution from a radiated power spectrum. We study the deviations from the ideal blackbody spectrum or the spectral distortions by incorporating first a non-zero chemical potential $\mu$ via the Bose-Einstein distribution and then the Compton parameter $y$ while keeping the monopole temperature constant. We infer the results as probability distribution functions on these distortions. Finally, we derive $\mu = (8.913 \pm 0.736) \times 10^{-5}$ and $y = (1.532 \pm 0.092) \times 10^{-5}$ at a $68\%$ confidence interval. The results are consistent with prior values and provide tighter constraints on the CMB spectral distortion and synergies of the primordial Universe.

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Somita Dhal, Koustav Konar, R. K. Paul. 2024-11-05. Constraining $\mu$ and $y$ distortions in the Cosmic Microwave Background with COBE/FIRAS Data. https://arxiv.org/abs/2411.03056

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