Black Holes in the Red-sequence Elliptical Galaxies at Redshifts $\sim 0.7-2.5$: Not Dark Energy Source but Remanants of Little Red Dots

TL;DR

This study uses JWST observations to demonstrate that black holes in high-redshift elliptical galaxies are unlikely to be the source of dark energy, instead evolving into low-mass black holes in mature galaxies without requiring cosmological coupling.

Contribution

It provides strong evidence against black holes being the source of dark energy and explains the evolution of Little Red Dots into elliptical galaxies with black holes.

Findings

Black holes are not the source of dark energy at >10σ confidence.

Little Red Dots evolve into elliptical galaxies with low-mass black holes.

Black hole cosmological coupling is not supported by high-redshift observations.

Abstract

The nature of dark energy remains one of the most profound mysteries in modern cosmology. One intriguing proposal is that black holes (BHs) could be the astrophysical source of dark energy through a cosmological coupling mechanism, and strong evidence has been claimed via analyzing the growth of the black hole masses in the red-sequence elliptical galaxies at redshifts $\leq 2.5$. In this work, with a group of very high redshift AGNs detected by the James Webb Space Telescope (JWST) in the red-sequence elliptical galaxies, we show that the possibility of BHs being the astrophysical source of dark energy has been rejected at a confidence level exceeding 10$\sigma$. Moreover, it turns out that the Little Red Dots recently discovered by JWST, characterized by the low accretion rates, can naturally evolve into the red-sequence elliptical galaxies hosting the relatively low mass black holes at the redshifts of $\sim 0.7-2.5$, without the need of black hole cosmological coupling.