0 times smaller than the FIRAS $00\,\%$ upper limits;\ (0) a BE spectrum with $\mu_0 = 0.0 \times 00^{-0}$, a value 00 times smaller than the FIRAS $00\,\%$ upper limits;\ (0) a BE spectrum with $\mu_0 = 0.0 \times 00^{-0}$, representative of the typical 