RADIATIVELY INEFFICIENT ACCRETION IN NEARBY GALAXIES

By Luis C. Ho. 2009

209 citations recorded by the source corpus.

We use new central stellar velocity dispersions and nuclear X-ray and Hα luminosities for the Palomar survey of nearby galaxies to investigate the distribution of nuclear bolometric luminosities and Eddington ratios for their central black holes (BHs). This information helps to constrain the nature of their accretion flows and the physical drivers that control the spectral diversity of nearby active galactic nuclei. The characteristic values of the bolometric luminosities and Eddington ratios, which span over 7–8 orders of magnitude, from Lbol ≲ 1037 to 3 × 1044 erg s−1 and Lbol/LEdd ≈10−9 to 10−1, vary systematically with nuclear spectral classification, increasing along the sequence absorption-line nuclei → transition objects → low-ionization nuclear emission-line regions → Seyferts. The Eddington ratio also increases from early-type to late-type galaxies. We show that the very modest accretion rates inferred from the nuclear luminosities can be readily supplied through local mass loss from evolved stars and Bondi accretion of hot gas, without appealing to additional fueling mechanisms such as angular momentum transport on larger scales. Indeed, we argue that the fuel reservoir generated by local processes should produce far more active nuclei than is actually observed. This generic luminosity-deficit problem suggests that the radiative efficiency in these systems is much less than the canonical value of 0.1 for traditional optically thick, geometrically thin accretion disks. The observed values of Lbol/LEdd, all substantially below unity, further support the hypothesis that massive BHs in most nearby galaxies reside in a low or quiescent state, sustained by accretion through a radiatively inefficient mode.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/d8fcae43ed197a5a0e5b6d3fecc900384471e1c9

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In Astronomy and Astrophysics

Citations in the corpus

FEEDBACK FROM CENTRAL BLACK HOLES IN ELLIPTICAL GALAXIES: TWO-DIMENSIONAL MODELS COMPARED TO ONE-DIMENSIONAL MODELS (2010, background): “Lowredshift observational constraints for the fraction of 3 × 108M⊙ BHs accreting at 1% and 10% of the Eddington rate are taken from Heckman et al. (2004), Greene & Ho (2007), Ho (2009), and Kauffmann & Heckman (2009).”
Hot Accretion Flows Around Black Holes (2014, background): “The fact that the black holes are dim thus suggests that they must be accreting via a radiatively inefficient mode, i.e., a hot accretion flow (Fabian & Rees 1995, Di Matteo et al. 2000, Ho 2009, Russell et al. 2013b).”
ON THE DISAPPEARANCE OF THE BROAD-LINE REGION IN LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI (2009, methodology): “As discussed in Ho (2009a), these X-ray measurements can be converted to bolometric luminosities with an accuracy of ∼0.3 dex.”
THEORETICAL EVOLUTION OF OPTICAL STRONG LINES ACROSS COSMIC TIME (2013, background): “Optical and X-ray studies suggest that nuclear LINERs (< 1 kpc) are predominantly inefficiently accreting AGN, analogous to the ”low” state of black hole binary systems (Ho 2005; Satyapal et al. 2005; Kewley et al. 2006b; González-Mart́ın et al. 2009; Gu & Cao 2009; Ho 2009).”
General physical properties of bright Fermi blazars (2009, result): “Notably, there are hints that similar results holds forradio-quietsources (e.g. Ho 2009; see also Ho 2008 for review).”
FEEDBACK FROM CENTRAL BLACK HOLES IN ELLIPTICAL GALAXIES. III. MODELS WITH BOTH RADIATIVE AND MECHANICAL FEEDBACK (2010, result): “!) at the current epoch in these fiducial models in rough agreement with current observations (e.g., see Pellegrini 2005, Ho 2009).”
The black hole accretion code (2016, methodology): “Hence we solve for conservation of quantities in the Eulerian frame: the density D := −ρunν , the covariant threemomentum Sj , the rescaled energy density τ = U − D [4] (where U denotes the total energy density as seen by the Eulerian observer), and the Eulerian magnetic three-fields B .”
Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies (2013, background): “(Other caveats are discussed in Krolik 2001 and in Greene & Ho 2009.)”
Evolution of broad-line emission from active galactic nuclei (2013, methodology): “Further decrease of the accretion rate triggers the mass conservation limit found in Elitzur & Ho (2009), broad-line emission disappears and the AGN becomes a true type 2.”
The SAMI Galaxy Survey: shocks and outflows in a normal star-forming galaxy (2014, background): “It is unlikely that the outflows in SDSS J0900 are driven by the LLAGN unless, within approximately the dynamical timescale of the outflowing gas (107 yr), SDSS J0900 was a Seyfert galaxy where the AGN can be 103 times more energetic than a LLAGN (Ho 2009).”