Distant foreground and the Planck-derived Hubble constant

Abstract

It is possible to reduce the discrepancy between the local measurement of the cosmological parameter H 0 and the value derived from the Planck measurements of the Cosmic Microwave Background (CMB) by considering contamination of the CMB by emission from some medium around distant extragalactic sources, such as extremely cold coarse-grain dust. Though being distant, such a medium would still be in the foreground with respect to the CMB, and, as any other foreground, it would alter the CMB power spectrum. This could contribute to the dispersion of CMB temperature fluctuations. By generating a few random samples of CMB with different dispersions, we have checked that the increased dispersion leads to a smaller estimated value of H 0 , the rest of the cosmological model parameters remaining fixed. This might explain the reduced value of the Planck-derived parameter H 0 with respect to the local measurements. The signature of the distant foreground in the CMB traced by SNe was previously reported by the authors of this paper -we found a correlation between the SN redshifts, z SN , and CMB temperature fluctuations at the SNe locations, T SN . Here we have used the slopes of the regression lines T SN / z SN corresponding to different Planck wave bands in order to estimate the possible temperature of the distant extragalactic medium, which turns out to be very low, about 5 K. The most likely ingredient of this medium is coarse-grain (grey) dust, which is known to be almost undetectable, except for the effect of dimming remote extragalactic sources.

The KBC void and Hubble tension contradict $Λ$CDM on a Gpc scale $-$ Milgromian dynamics as a possible solution

“…Finally, we consider the possibility that the CMB is contaminated by intergalactic dust, which in turn would affect the H global 0 required by Planck Collaboration VI (2020). Some distant foreground emission can increase H global 0 (Yershov et al 2020), which would slightly reduce the mild tension between our model and the strong lensing data (Figure 7). This is because the z > 0.4 lenses all give H 0 systematically above the Planck prediction by a similar extent.…”

“…The H 0 values from the four highest redshift lenses of Wong et al (2020) give a median (mean) of 71.3 km s −1 Mpc −1 (70.8 km s −1 Mpc −1 ), which is 3.9 km s −1 Mpc −1 (3.4 km s −1 Mpc −1 ) higher than the Planck prediction. This systematic offset can be reduced if the background H 0 is underestimated due to errors in the Planck measurements caused by intergalactic dust (Yershov et al 2020; see also Vavryčuk 2018Vavryčuk , 2019. We discuss this issue further in Section 5.3.8.…”

On the Galactic Halos Rotation by Planck Data

“…It has been suggested that galactic halos contain interstellar dust grain fraction of about 1-3% in mass, and the rest is H 2 , He and other heavier molecules [31,32]. Halo dust grains are expected to be at a slightly higher temperature with respect to that of the gas, about 5 K or so, depending on the cloud position within the galactic halo [33], but as a first approximation, we assume here that dust and gas are at the same temperature, i.e., 2.7 K.…”

The Hubble Diagram: Jump from Supernovae to Gamma-ray Bursts

“…This led to the introduction of dark energy into the standard cosmological model (SCM) [4,5]. However, there is still a wide discussion on cosmological models and their parameter values [6][7][8][9]. The wCDM model, where the ΛCDM model is a special case of one, is often considered an alternative to SCM.…”