A novel Bayesian approach for decomposing the radio emission of quasars – II. Link between quasar radio emission and black hole mass

Yue, B H; Duncan, K J; Best, P N; Arnaudova, M I; Morabito, L K; Petley, J W; Röttgering, H J A; Shenoy, S; Smith, D J B

Abstract

Whether the mass of supermassive black hole ( M BH ) is directly linked to the quasar radio luminosity remains a long-debated issue, and understanding the role of M BH in the evolution of quasars is pivotal to unveiling the mechanism of active galactic nucleus (AGN) feedback. In this work, based on a two-component Bayesian model, we examine how M BH affects the radio emission from quasars, separating the contributions from host galaxy star formation (SF) and AGN activity. By modelling the radio flux density distribution of Sloan Digital Sky Survey quasars from the LOFAR Two-metre Sky Survey Data Release 2, we find no correlation between M BH and star formation rate (SFR) at any mass for quasars at a given redshift and bolometric luminosity. The same holds for AGN activity across most M BH values; however, quasars with the top 20 per cent most massive supermassive black holes (SMBHs) are two to three times more likely to host strong radio jets than those with lower mass SMBHs at similar redshift and luminosity. We suggest defining radio quasar populations by their AGN and SF contributions instead of radio loudness; our new definition unifies previously divergent observational results on the role of M BH in quasar radio emissions. We further demonstrate that this radio enhancement in quasars with the 20 per cent most massive SMBHs affects only the ∼ 5 per cent most radio bright quasars at a given redshift and bolometric luminosity. We discuss possible physical origins of this radio excess in the most massive and radio-bright quasar population, which remains an interest for future study.

Citation

Yue, B. H., Duncan, K. J., Best, P. N., Arnaudova, M. I., Morabito, L. K., Petley, J. W., Röttgering, H. J. A., Shenoy, S., & Smith, D. J. B. (2025). A novel Bayesian approach for decomposing the radio emission of quasars – II. Link between quasar radio emission and black hole mass. Monthly Notices of the Royal Astronomical Society, 537(2), 858-875. https://doi.org/10.1093/mnras/staf077

• Journal Article Type: Article
• Acceptance Date: Jan 13, 2025
• Online Publication Date: Jan 15, 2025
• Publication Date: Jan 23, 2025
• Deposit Date: Feb 10, 2025
• Publicly Available Date: Feb 12, 2025
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 537
• Issue: 2
• Pages: 858-875
• DOI: https://doi.org/10.1093/mnras/staf077
• Keywords: black hole physics –galaxies: active –quasars: general –quasars: supermassive black holes –radio continuum: galaxies.
• Public URL: https://durham-repository.worktribe.com/output/3475949