Can cosmologically-coupled mass growth of black holes solve the mass gap problem?

Understand

Observations of elliptical galaxies suggest that black holes (BHs) might serve as dark energy candidates, coupled to the expansion of the Universe.

• According to this hypothesis, the mass of a BH could increase as the Universe expands.
• BH low-mass X-ray binaries (LMXBs) in the Galactic disk were born several gigayears ago, making the coupling effect potentially significant.
• In this work, we calculate the evolution of BH binaries with a binary population synthesis method to examine the possible influence of cosmologically-coupled growth of BHs, if it really exists.