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Probing black hole accretion tracks, scaling relations, and radiative efficiencies from stacked X-ray active galactic nuclei

Zanisi, Lorenzo; Villforth, Carolin; Suh, Hyewon; Sheth, Ravi K.; Rodighiero, Giulia; Ricci, Federica; Mezcua, Mar; Menci, Nicola; Lu, Youjun; Lapi, Andrea; La Franca, Fabio; Duras, Federica; Delvecchio, Ivan; Daddi, Emanuele; Civano, Francesca; Calderone, Giorgio; Bongiorno, Angela; Ananna, Tonima T.; Allevato, Viola; Alexander, David M.; Carraro, Rosamaria; Fu, Hao; Moster, Benjamin; Yang, Guang; Bernardi, Mariangela; Grylls, Philip J.; Marsden, Christopher; Weinberg, David H.; Shankar, Francesco

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Lorenzo Zanisi

Carolin Villforth

Hyewon Suh

Ravi K. Sheth

Giulia Rodighiero

Federica Ricci

Mar Mezcua

Nicola Menci

Youjun Lu

Andrea Lapi

Fabio La Franca

Federica Duras

Ivan Delvecchio

Emanuele Daddi

Francesca Civano

Giorgio Calderone

Angela Bongiorno

Tonima T. Ananna

Viola Allevato

Rosamaria Carraro

Hao Fu

Benjamin Moster

Guang Yang

Mariangela Bernardi

Philip J. Grylls

Christopher Marsden

David H. Weinberg

Francesco Shankar


The masses of supermassive black holes at the centres of local galaxies appear to be tightly correlated with the mass and velocity dispersions of their galactic hosts. However, the local Mbh–Mstar relation inferred from dynamically measured inactive black holes is up to an order-of-magnitude higher than some estimates from active black holes, and recent work suggests that this discrepancy arises from selection bias on the sample of dynamical black hole mass measurements. In this work, we combine X-ray measurements of the mean black hole accretion luminosity as a function of stellar mass and redshift with empirical models of galaxy stellar mass growth, integrating over time to predict the evolving Mbh–Mstar relation. The implied relation is nearly independent of redshift, indicating that stellar and black hole masses grow, on average, at similar rates. Matching the de-biased local Mbh–Mstar relation requires a mean radiative efficiency ε ≳ 0.15, in line with theoretical expectations for accretion on to spinning black holes. However, matching the ‘raw’ observed relation for inactive black holes requires ε ∼ 0.02, far below theoretical expectations. This result provides independent evidence for selection bias in dynamically estimated black hole masses, a conclusion that is robust to uncertainties in bolometric corrections, obscured active black hole fractions, and kinetic accretion efficiency. For our fiducial assumptions, they favour moderate-to-rapid spins of typical supermassive black holes, to achieve ε ∼ 0.12–0.20. Our approach has similarities to the classic Soltan analysis, but by using galaxy-based data instead of integrated quantities we are able to focus on regimes where observational uncertainties are minimized.


Zanisi, L., Villforth, C., Suh, H., Sheth, R. K., Rodighiero, G., Ricci, F., …Shankar, F. (2020). Probing black hole accretion tracks, scaling relations, and radiative efficiencies from stacked X-ray active galactic nuclei. Monthly Notices of the Royal Astronomical Society, 493(1), 1500-1511.

Journal Article Type Article
Acceptance Date Dec 9, 2019
Online Publication Date Dec 16, 2019
Publication Date 2020-03
Deposit Date Nov 4, 2020
Publicly Available Date Nov 4, 2020
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 493
Issue 1
Pages 1500-1511
Public URL


Published Journal Article (1 Mb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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