Dark matter solution to the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>H</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>S</mml:mi><mml:mn>8</mml:mn></mml:msub></mml:math> tensions, and the integrated Sachs-Wolfe void anomaly
Krishna Naidoo, Mariana Jaber, Wojciech A. Hellwing, Maciej Bilicki
Abstract
We consider a phenomenological model of dark matter with an equation-of-state $w$ that is negative and changing at late times. We show this couples the ${H}_{0}$ and ${S}_{8}$ tensions, alleviating them both simultaneously, reducing the ${H}_{0}$ tension from $\ensuremath{\sim}5\ensuremath{\sigma}$ to $\ensuremath{\sim}3\ensuremath{\sigma}$ and the ${S}_{8}$ tension from $\ensuremath{\sim}3\ensuremath{\sigma}$ to $\ensuremath{\sim}1\ensuremath{\sigma}$. Furthermore, the model provides an explanation for the anomalously large integrated Sachs-Wolfe (ISW) effect from cosmic voids, a unique consequence of the changing and negative equation-of-state. Observations of high ISW from cosmic voids may therefore be evidence that dark matter plays a significant role in both the ${H}_{0}$ and ${S}_{8}$ tensions. We predict the ISW from cosmic voids to be a factor of up to $\ensuremath{\sim}2$ greater in this model than what is expected from the standard model $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$. These results extend to other degenerate models of dark matter, such as unified or interacting dark matter and dark energy models.