Evidence for strong progenitor age dependence of type Ia supernova luminosity standardization process

Abstract

Supernova (SN) cosmology is based on the assumption that the width-luminosity relation (WLR) and the color-luminosity relation (CLR) in the type Ia SN luminosity standardization would not vary with progenitor age. Unlike this expectation, recent age datings of stellar populations in host galaxies have shown significant correlations between progenitor age and Hubble residual (HR). It was not clear, however, how this correlation arises from the SN luminosity standardization process, and how this would impact the cosmological result. Here we show that this correlation originates from a strong progenitor age dependence of the WLR and the CLR, in the sense that SNe from younger progenitors are fainter each at given light-curve parameters x 1 and c. This is reminiscent of Baade's discovery of two Cepheid period-luminosity relations, and, as such, causes a serious systematic bias with redshift in SN cosmology. Other host properties show substantially smaller and insignificant differences in the WLR and CLR for the same dataset. We illustrate that the differences between the high-z and low-z SNe in the WLR and CLR, and in HR after the standardization, are fully comparable to those between the correspondingly young and old SNe at intermediate redshift, indicating that the observed dimming of SNe with redshift is most likely an artifact of over-correction in the luminosity standardization. When this systematic bias with redshift is properly taken into account, there is no or little evidence left for an accelerating universe, posing a serious question to one of the cornerstones of the concordance model.

An imaging polarimetry survey of Type Ia supernovae: are peculiar extinction and polarization properties produced by circumstellar or interstellar matter?

“…If true, SN Ia luminosity evolution can have a high impact on cosmology, because stellar populations get younger with increasing redshift. Ho we ver, the result is highly debated and unlikely to be correct (Lee et al 2020b(Lee et al , 2021Rose et al 2020 ;Murakami et al 2021 ;Zhang et al 2021 ). Zelaya et al ( 2017 ) have shown that the polarization angles of reddened SNe Ia tend to be aligned with galactic features, notably the spiral arms of the host galaxies.…”

Revealing Intrinsic Flat $Λ$CDM Biases with Standardizable Candles

“…However, in contrast to SN, there is considerable intrinsic scatter in QSO fluxes. As with SN in the 1990s [40], before corrections for color, shape and host galaxy mass [41,42] (however, see [43][44][45][46] for ongoing debate), this scatter necessitates an additional intrinsic dispersion parameter δ. Given corrections made to SN since the 1990s, it is worth bearing in mind that (1) is a working proposal and future corrections may be necessary, especially in light of criticisms [47][48][49].…”

Fitting of supernovae without dark energy

“…This has led several researchers to point out that an evolution of SNe Ia luminosity can fit their Hubble-Lemaître diagram without dark energy. [22][23][24][25][26][27]…”