Disentangling stellar, gas, and dark matter contributions to QSO1’s dynamical mass

Ascertain the relative contributions of stars, gas, and dark matter to the dynamical mass inferred from JWST NIRSpec-IFU kinematics of Abell2744-QSO1, which could not be disentangled with the current data due to the lack of emission tracers of gas on larger scales.

Background

The paper establishes a direct, dynamical black hole mass for the z=7.04 Little Red Dot Abell2744-QSO1 and shows that the kinematics are best explained by Keplerian rotation around a point mass. While they place conservative upper limits on any extended stellar component and argue that stars cannot dominate the mass budget, the authors note that dynamical mass measures at these scales are sensitive to combined contributions from stars, gas, and dark matter.

Due to the lack of emission tracers of gas on larger scales in the current dataset, the authors cannot separate these components, leaving unresolved the precise partitioning of the extended mass. Clarifying these contributions is important for tightening constraints on the host galaxy’s stellar mass and for interpreting the extreme mass ratio M_BH/M_* in the context of black hole seeding scenarios.