English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The comparison of the black hole mass function (BHMF) of active galactic nuclei (AGN) relics with the measured mass function of the massive black holes in galaxies provides strong evidence for the growth of massive black holes being dominated by mass accretion. We derive the Eddington ratio distributions as functions of black hole mass and redshift from a large AGN sample with measured Eddington ratios given by Kollmeier et al. We find that, even at the low‐mass end, most black holes are accreting at Eddington ratio  λ∼ 0.2 , which implies that the objects accreting at extremely high rates should be rare or such phases are very short. Using the derived Eddington ratios, we explore the cosmological evolution of massive black holes with an AGN bolometric luminosity function (LF). It is found that the resulted BHMF of AGN relics is unable to match the measured local BHMF of galaxies for any value of (constant) radiative efficiency  η rad  . Motivated by Volonteri, Sikora &amp; Lasota's study on the spin evolution of massive black holes, we assume the radiative efficiency to be dependent on black hole mass, i.e.  η rad   is low for   M  bh  &lt; 10 8  M⊙  and it increases with the black hole mass for   M  bh ≥ 10 8  M⊙ . We find that the BHMF of AGN relics can roughly reproduce the local BHMF of galaxies if  η rad ≃ 0.08  for   M  bh  &lt; 10 8  M⊙  and it increases to ≳0.18 for   M  bh ≳ 10 9  M⊙ , which implies that most massive black holes  (≳10 9  M⊙)  are spinning very rapidly.

Rapidly spinning massive black holes in active galactic nuclei: evidence from the black hole mass function