Tsallis-Cirto Hubble parameter: Explaining DESI data and High redshift Supermassive Black Hole

Abstract

Phantom dark energy from DESI DR2 BAO [1]-[3] and observations of very high redshift Supermassive Black Holes (SMBH) present two new major challenges in cosmology and astrophysics. In this work, we find that the Hubble parameter in the Tsallis-Cirto (TC) cosmology is consistent with Cosmic Chronometers (CC) and DESI DR2 data upto z<2.33, while matching the observed CMB acoustic angular scale constraint. We use this TC Hubble parameter and a new metric solution in [4] to examine the SMBH formation timeline and find that the modified over-density evolution due to the metric leads to higher virialised redshifts for the first stars and provides sufficient cosmological time for the formation of SMBHs at high redshifts.