Direct Tests of Black Hole Accretion Rate Prescriptions. I. Bondi Accretion at Different Scales

August 2026 • 2026ApJ..1007...23A

Authors • Agostino, James • Lin, Ming-Yi • Jones, Natasha • Medling, Anne M. • Barcos-Muñoz, Loreto • Anglés-Alcázar, Daniel • Ricci, Claudio • Privon, George C. • U, Vivian • Torrey, Paul • Hopkins, Philip F. • Max, Claire

Abstract • We present spatially resolved parsec-scale measurements of nuclear conditions (gas density and kinetic temperature) relevant for black hole accretion rate predictions in the Seyfert 2 galaxy, NGC 1068. We inject these parameters into the prescription for a Bondi-like accretion model, then compare the resulting accretion rate prediction to the empirical accretion rate derived from hard X-ray observations. Cosmological simulations have spatial resolution ranging from ∼10 pc to approximately kiloparsec scales, and so for reasonable comparison we test these accretion rate predictions in pixel-sized radial steps out to 500 pc. Compared to warm H₂ gas, CO gas is the dominant mass carrier close to the SMBH. We find that the Bondi accretion rate ( ṀBondi ) of cold molecular gas alone (measured using CO) overestimates the true accretion rate by up to 14 dex in a small aperture (r ≲5 pc) around the black hole, and by at least 8 dex inside large apertures (r ≲500 pc). These results are the first in a series of direct tests of accretion rate prescriptions, and they suggest that using a Bondi accretion formalism to model supermassive black hole accretion in Seyfert 2 galaxies may lead to overestimated accretion rates in simulations.

Links

• PDF https://iopscience.iop.org/article/10.3847/1538-4357/ae80ca/pdf
• ELECTR https://doi.org/10.3847/1538-4357/ae80ca