A Population III–Generated Dust Screen at z ∼ 16

Abstract

The search for alternative cosmological models is largely motivated by the growing discordance between the predictions of ΛCDM and the ever-improving observations, such as the disparity in the value of H 0 measured at low and high redshifts. One model in particular, known as the R h = ct universe, has been highly successful in mitigating or removing all of the inconsistencies. In this picture, however, the anisotropies in the cosmic microwave background (CMB) would have emerged at a redshift z ∼ 16, rather than via fluctuations in the recombination zone at z ∼ 1080. We demonstrate here that a CMB created in the early universe, followed by scattering through a Population III–generated dust screen, is consistent with all of the current data. Indeed, the Planck measurements provide a hint of an ∼2%–4% frequency dependence in the CMB power spectrum, which would be naturally explained as a variation in the optical depth through the dust but not a Thomson scattering–dominated recombination environment. Upcoming measurements should be able to easily distinguish between these two scenarios, e.g., via the detection of recombination lines at z ∼ 1080, which would completely eliminate the dust-reprocessing idea.

The many tensions with dark-matter based models and implications on the nature of the Universe

“…Such ideas are not new, with Rees (1978 ([253], see also [254,255] and references therein) having proposed that the CMB may have been produced by the first star formation with reprocessing of the stellar emission through dust. In the context of the MMoC (the 𝑅 h = 𝑐 𝑡 model), Melia (2022, [186]) suggests the CMB to be the (standard) surface of last scattering or photosphere produced at 𝑧 e ≈ 1100, just as in the SMoC, but the temperature fluctuations in it to stem from 𝑧 e ≈ 16 as a consequence of the CMB photons scattering on dust produced by the first generations of stars. [186] notes evidence for this through the frequency dependence in the CMB power spectrum observed by the Planck satellite.…”

“…In the context of the MMoC (the 𝑅 h = 𝑐 𝑡 model), Melia (2022, [186]) suggests the CMB to be the (standard) surface of last scattering or photosphere produced at 𝑧 e ≈ 1100, just as in the SMoC, but the temperature fluctuations in it to stem from 𝑧 e ≈ 16 as a consequence of the CMB photons scattering on dust produced by the first generations of stars. [186] notes evidence for this through the frequency dependence in the CMB power spectrum observed by the Planck satellite. Vavrycuk (2018, [256]) suggests the CMB to be entirely dust-reprocessed star light over cosmological distances, given the observed traces of dust between galaxies in the present-day Universe (i.e., the present-day observed intergalactic dust density leads to an emission over cosmological distances that, according to the calculation presented in [256], is comparable to the observed CMB spectral energy distribution).…”