2008/08/31 by Priyamvada Natarajan, Ezequiel Treister · 86 citations
Earth and Planetary Sciences · Physics and Astronomy · #Accretion (finance) #Active galactic nucleus #Astronomy and Astrophysical Research #Black hole (networking) #Bulge #Earth Systems and Cosmic Evolution #Eddington luminosity #Galaxies: Formation, Evolution, Phenomena #Galaxy #Luminosity function #Quasar #Redshift #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2008.13864.x
published in Monthly Notices of the Royal Astronomical Society 393(3), 838-845 (Oxford University Press) · 9 pages, 4 figures. MNRAS accepted, references updated
arxiv created 2008/08/31 · openalex publication_date 2009/01/31 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We make a case for the existence for ultra-massive black holes (UMBHs) in the Universe, but argue that there exists a likely upper limit to black hole (BH) masses of the order of M∼ 1010 M⊙. We show that there are three strong lines of argument that predicate the existence of UMBHs: (i) expected as a natural extension of the observed BH mass bulge luminosity relation, when extrapolated to the bulge luminosities of bright central galaxies in clusters; (ii) new predictions for the mass function of seed BHs at high redshifts predict that growth via accretion or merger-induced accretion inevitably leads to the existence of rare UMBHs at late times; (iii) the local mass function of BHs computed from the observed X-ray luminosity functions of active galactic nuclei predict the existence of a high-mass tail in the BH mass function at z= 0. Consistency between the optical and X-ray census of the local BH mass function requires an upper limit to BH masses. This consistent picture also predicts that the slope of the Mbh–σ relation will evolve with redshift at the high-mass end. Models of self-regulation that explain the co-evolution of the stellar component and nuclear BHs naturally provide such an upper limit. The combination of multiwavelength constraints predicts the existence of UMBHs and simultaneously provides an upper limit to their masses. The typical hosts for these local UMBHs are likely the bright, central cluster galaxies in the nearby Universe.