The luminosity dependence of the type 1 active galactic nucleus fraction

By C. Simpson. 2005

234 citations recorded by the source corpus.

Using a complete, magnitude-limited sample of active galaxies from the Sloan Digital Sky Survey, we show that the fraction of broad-line (type 1) active galactic nuclei (AGNs) increases with luminosity of the isotropically emitted [O III] narrow emission line. Our results are quantitatively in agreement with, and far less uncertain than, similar trends found from studies of X-ray and radio-selected active galaxies. While the correlation between broad-line fraction and luminosity is qualitatively consistent with the receding torus model, its slope is shallower and we therefore propose a modification to this model where the height of the torus increases slowly with AGN luminosity. We demonstrate that the faint-end slope of the AGN luminosity function steepens significantly when a correction for 'missing' type 2 objects is made, and that this can substantially affect the overall AGN luminosity density extrapolated from samples of more luminous objects.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/a56fda4c46a43d8b49057ac17b7512b1a4b8ff34

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Citations in the corpus

The incidence of obscuration in active galactic nuclei (2013, background): “…fraction of absorbed AGN, defined in different and often independent ways, appears to be lower at higher nuclear luminosities (Lawrence & Elvis 1982; Steffen et al. 2003; Ueda et al. 2003; Simpson 2005; Hasinger 2008; Bongiorno et al. 2010; Brusa et al. 2010; Burlon et al. 2011; Assef et al. 2013).”
THREE-YEAR SWIFT–BAT SURVEY OF ACTIVE GALACTIC NUCLEI: RECONCILING THEORY AND OBSERVATIONS? (2010, background): “Nonetheless, one has to consider that (1) the torus is likely clumpy, (2) H/R is a function of luminosity (Simpson 2005), and (3) that even if the dusty components of the torus do absorb optical, UV, and X-ray photons, X-ray obscuration can take place also in the—dust free—inner region, in the…”
SPACE DENSITY OF OPTICALLY SELECTED TYPE 2 QUASARS (2008, background): “Simpson (2005) also clearly finds the decreasing trend in type 2 fraction with luminosity, but found substantially higher type 2 fractions (open diamonds).”
TORUS AND ACTIVE GALACTIC NUCLEUS PROPERTIES OF NEARBY SEYFERT GALAXIES: RESULTS FROM FITTING INFRARED SPECTRAL ENERGY DISTRIBUTIONS AND SPECTROSCOPY (2011, background): “Observational (e.g., Simpson 2005) and theoretical (e.g., Hönig & Beckert 2007) arguments provide evidence of the so-called receding torus (Lawrence 1991).”
MOLECULAR GAS IN z ∼ 6 QUASAR HOST GALAXIES (2010, background): “Recent studies showed that the unobscured fraction of quasars is increasing with quasar luminosity, and for objects with Lbol ≥ 10 13 L⊙, this fraction is probably larger than 50% (Simpson 2005; Treister et al. 2008).”
OBSCURATION-DEPENDENT EVOLUTION OF ACTIVE GALACTIC NUCLEI (2015, background): “Luminosity-dependence and evolution of the obscured fraction Previous studies suggest that the fraction of obscured AGN is a function of accretion luminosity (e.g. Lawrence 1991; Ueda et al. 2003; Simpson 2005; Akylas et al. 2006; Silverman et al. 2008; Burlon et al. 2011; Ueda et al. 2014).”
MID-INFRARED SELECTION OF ACTIVE GALACTIC NUCLEI WITH THE WIDE-FIELD INFRARED SURVEY EXPLORER. II. PROPERTIES OF WISE-SELECTED ACTIVE GALACTIC NUCLEI IN THE NDWFS BOÖTES FIELD (2012, methodology): “Note that because Simpson (2005) used [O iii] luminosities as proxies for the accretion disk luminosity, we must fit for LAGN,0, obtaining respectively 1.12+0.16−0.14 × 1045 erg s−1 (ψ = 0) and 1.98+0.57−0.44 × 1045 erg s−1 (ψ = 0.23).”
CHASING HIGHLY OBSCURED QSOs IN THE COSMOS FIELD (2008, methodology): “…estimated the density of CT AGN at three luminosities, by comparing the luminosity function of optically selected, narrow line AGN in the SDSS (Simpson 2005), which must include both CT and Compton-thin AGN, to the luminosity function of X-ray selected Compto-thin AGN, rescaled at z=0 using…”
Fueling Low-Level AGN Activity through Stochastic Accretion of Cold Gas (2006, methodology): “…(108) and (109) and the functional form of empirical calculations which allow for e.g. evolution of the inner torus radius and torus height as a function of luminosity (e.g., Simpson 2005), suggesting that feedback balance does capture the critical dependence on black hole and fueling properties.”
Active galactic nuclei: what’s in a name? (2017, background): “of the accretion disk (Ueda et al., 2003; Hasinger, 2004; Simpson, 2005; Hatziminaoglou et al., 2008; Assef et al., 2013; Mateos et al., 2016), an effect typically referred to as”
A Unified, Merger-driven Model of the Origin of Starbursts, Quasars, the Cosmic X-Ray Background, Supermassive Black Holes, and Galaxy Spheroids (2005, methodology): “…torus models have been proposed which give a better fit to the data by, for example, allowing the torus height to vary with luminosity (e.g., Simpson 2005), but there is no particular physical motivation for such changes, and theseintroduce such variation through additional free…”
Tracing the cosmic growth of supermassive black holes to z ∼ 3 with Herschel (2014, background): “While the dependence of NH (hydrogen column density) on the intrinsic AGN luminosity is currently well established (Lawrence 1991; Simpson 2005; Ueda et al. 2003; Steffen et al. 2003; Barger & Cowie 2005; Sazonov et al. 2007; Lusso et al. 2013), the evolution with redshift is still debated: on the…”
Revisiting the Unified Model of Active Galactic Nuclei (2015, methodology): “For example, Simpson (2005) measured the fraction of type-I sources by using [O iii]λ5007 luminosities in SDSS AGNs and constructing LFs for the two types of AGNs.”
TOWARD THE STANDARD POPULATION SYNTHESIS MODEL OF THE X-RAY BACKGROUND: EVOLUTION OF X-RAY LUMINOSITY AND ABSORPTION FUNCTIONS OF ACTIVE GALACTIC NUCLEI INCLUDING COMPTON-THICK POPULATIONS (2014, background): “Besides the well established anti-correlation of absorption fraction with luminosity (e.g., Ueda et al. 2003; Steffen et al. 2003; Simpson 2005), several works have reported that the fraction of absorbed AGNs increased toward higher redshift fromz = 0 to z> 1 (La Franca et al. 2005; Ballantyne et…”
Cosmic X-ray surveys of distant active galaxies (2015, background): “Results from recent infrared (e.g., Ballantyne et al 2006; Treister et al 2008; Assef et al 2013; Lusso et al 2013; Toba et al 2014) and optical (e.g., Simpson 2005) surveys broadly confirm this basic revision of orientation-based unification models (but see Lawrence and Elvis 2010).”
AGN Dusty Tori. II. Observational Implications of Clumpiness (2008, background): “This has been verified in a large number of observations that estimate the luminosity dependence of either f2 or f1 (the fraction of unobscured sources), or differences between the luminosity functions of type 1 and 2 AGNs (see Hao et al. 2005; Simpson 2005; Maiolino et al. 2007).”
The AGN-obscuring Torus: The End of the “Doughnut” Paradigm? (2006, unknown): “The fraction of type 2 objects appears to decrease with L , in accordance with the “receding torus” model (Simpson 2005).”