Alleviating the Hubble-constant tension and the growth tension via a transition of absolute magnitude favored by the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>Pantheon</mml:mi><mml:mo>+</mml:mo></mml:mrow></mml:math> sample
Yang Liu, Hongwei Yu, Puxun Wu
Abstract
We establish a cosmological-model-independent method to extract the apparent magnitude and its derivative at different redshifts from the $\mathrm{Pantheon}+$ type Ia supernova sample and find that the obtained values deviate clearly from the prediction of the $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model at the lowest redshift. This deviation can be explained as a result of a transition of the absolute magnitude $M$ in the low-redshift region. The observations seem to favor this transition, since the minimum values of ${\ensuremath{\chi}}^{2}$ for two Ans\"atze of a varying $M$ are less than that of a constant $M$. The Hubble-constant tension is alleviated from larger than $5\ensuremath{\sigma}$ to be about $1\ensuremath{\sigma}--2\ensuremath{\sigma}$ for a varying $M$, and the growth tension can be resolved after attributing the variation of $M$ to a modification of the effective Newton's constant.