Active Galactic Nucleus Emission‐Line Properties Versus the Eddington Ratio

Warner, C.; Hamann, Fred; Dietrich, M.

doi:10.1086/386325

Cited by 108 publications

(143 citation statements)

References 79 publications

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“…However, our model predicts mean accretion rates that are up to ∼0.5 dex higher than the observed distributions and a much larger fraction of AGNs accreting at super-Eddington ratesas high as 50% of the population for the most luminous AGNs (L bol 10 46.5 erg s −1 ). Such sources could correspond to the luminous Type 2 AGN population, indicating such sources are the most rapidly accreting sources (e.g., Warner et al 2004;Urrutia et al 2012). However, the uncertainties in virial SMBH mass estimates, used to derive the Eddington ratios, can introduce substantial biases into the observed distributions (e.g., Shen et al 2008;Shen & Kelly 2010;Schulze & Wisotzki 2011), potentially bringing them more in line with the predictions of our model.…”

Section: The Nature Of the Agn Populationmentioning

confidence: 67%

PRIMUS: AN OBSERVATIONALLY MOTIVATED MODEL TO CONNECT THE EVOLUTION OF THE ACTIVE GALACTIC NUCLEUS AND GALAXY POPULATIONS OUT TOz∼ 1

Aird¹,

Coil²,

Moustakas³

et al. 2013

ApJ

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We present an observationally motivated model to connect the active galactic nucleus (AGN) and galaxy populations at 0.2 < z < 1.0 and predict the AGN X-ray luminosity function (XLF). We start with measurements of the stellar mass function of galaxies (from the Prism Multi-object Survey) and populate galaxies with AGNs using models for the probability of a galaxy hosting an AGN as a function of specific accretion rate. Our model is based on measurements indicating that the specific accretion rate distribution is a universal function across a wide range of host stellar masses with slope γ 1 ≈ −0.65 and an overall normalization that evolves with redshift. We test several simple assumptions to extend this model to high specific accretion rates (beyond the measurements) and compare the predictions for the XLF with the observed data. We find good agreement with a model that allows for a break in the specific accretion rate distribution at a point corresponding to the Eddington limit, a steep power-law tail to super-Eddington ratios with slope γ 2 = −2.1 +0.3 −0.5 , and a scatter of 0.38 dex in the scaling between black hole and host stellar mass. Our results show that samples of low luminosity AGNs are dominated by moderately massive galaxies (M * ∼ 10 10 -10 11 M ) growing with a wide range of accretion rates due to the shape of the galaxy stellar mass function rather than a preference for AGN activity at a particular stellar mass. Luminous AGNs may be a severely skewed population with elevated black hole masses relative to their host galaxies and in rare phases of rapid accretion.

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Section: The Nature Of the Agn Populationmentioning

confidence: 67%

PRIMUS: AN OBSERVATIONALLY MOTIVATED MODEL TO CONNECT THE EVOLUTION OF THE ACTIVE GALACTIC NUCLEUS AND GALAXY POPULATIONS OUT TOz∼ 1

Aird¹,

Coil²,

Moustakas³

et al. 2013

ApJ

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“…Another interesting aspect of assessing the chemical composition of AGNs is that it provides clues on the co-evolution between galaxies and their supermassive black holes (SMBHs), which has been inferred by the tight correlation between the mass of SMBHs (M BH ) and their host spheroidal observed in the local Universe (e.g., Marconi & Hunt 2003;Ferrarese & Merritt 2000;Gebhardt et al 2000). Matsuoka et al (2011) reported a tight relationship between the metallicity in broad-line regions (BLRs) and M BH at z ∼ 2−3, suggesting that the evolution of SMBHs is associated with the cumulative star formation in the host galaxies (see also Warner et al 2004;Nagao et al 2006b).…”

Section: Introductionmentioning

confidence: 99%

Near-infrared spectroscopy of a nitrogen-loud quasar SDSS J1707+6443

Araki

Nagao

Matsuoka

et al. 2012

A&A

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We present near-infrared spectroscopy of the z 3.2 quasar SDSS J1707+6443, obtained with MOIRCS on the Subaru Telescope. This quasar is classified as a "nitrogen-loud" quasar because of the fairly strong N iii] and N iv] semi-forbidden emission lines from the broad-line region (BLR) observed in its rest-frame UV spectrum. However, our rest-frame optical spectrum from MOIRCS shows strong [O iii] emission from the narrow-line region (NLR), suggesting that, at variance with the BLR, NLR gas is not metal-rich. To reconcile these contradictory results, there may be two alternative possibilities: (1) the strong nitrogen lines from the BLR are simply caused by a very high relative abundance of nitrogen and not by a very high BLR metallicity, or (2) the BLR metallicity is not representative of the metallicity of the host galaxy, which is better traced by the NLR. In either case, the strong broad nitrogen lines in the UV spectrum are ot indication of a chemically enriched host galaxy. We estimated the black hole mass and Eddington ratio of this quasar from the velocity width of both C iv and Hβ, which results in log(M BH /M ) = 9.50 and log(L bol /L Edd ) = −0.34. The relatively high Eddington ratio is consistent with our earlier result that strong nitrogen emission from BLRs is associated with high Eddington ratios. Finally, we detected significant [Ne iii] emission from the NLR, implying a quite high gas density of n e ∼ 10 6 cm −3 and suggesting a strong coupling between quasar activity and dense interstellar clouds in the host galaxy.

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“…The metallicities in the BLR were found to be supersolar, reaching 10 Z in some cases, and to be correlated with the AGN luminosity, accretion rate, and BH mass (e.g. Hamann & Ferland 1993;Shemmer et al 2004;Warner et al 2004;Nagao et al 2006;Matsuoka et al 2011), with almost no redshift evolution. This is usually interpreted in Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck-Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC) and on observations collected at the European Organisation for Astronomical Reasearch in the Southern Hemisphere, Chile (program 070.B-0418).…”

Section: Introductionmentioning

confidence: 99%

The low-metallicity QSO HE 2158 − 0107: a massive galaxy growing by accretion of nearly pristine gas from its environment?

Wisotzki

Jahnke

Sánchez

2011

A&A

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The metallicities of active galactic nuclei (AGN) are usually well above solar in their narrow-line regions, often reaching up to several times solar in their broad-line regions independent of redshift. Low-metallicity AGN are rare objects that have so far always been associated with low-mass galaxies hosting low-mass black holes (M BH 10 6 M ). We present integral field spectroscopy data of the low-redshift (z = 0.212) quasi-stellar object (QSO) HE 2158−0107 for which we find strong evidence of sub-solar NLR metallicities associated with a massive black hole (M BH ∼ 3 × 10 8 M ). The QSO is surrounded by a large extended emission-line region reaching out to 30 kpc from the QSO in a tail-like geometry. We present optical and near-infrared images and investigate the properties of the host galaxy. The host of HE 2158−0107 is most likely a very compact bulge-dominated galaxy with a size of r e ∼ 1.4 kpc. The multi-colour spectral energy distribution (SED) of the host is quite blue, indicative of a significant young age stellar population formed within the last 1 Gyr. A 3σ upper limit of L bulge,H < 4.5 × 10 10 L ,H for the H-band luminosity and a corresponding stellar mass upper limit of M bulge < 3.4 × 10 10 M show that the host is offset from the local black hole-bulge relations. This is independently supported by the kinematics of the gas. Although the stellar mass of the host galaxy is lower than expected, it cannot explain the exceptionally low metallicity of the gas. We suggest that the extended emission-line region and the galaxy growth are caused by the infall of nearly pristine gas from the environment of the QSO host. Minor mergers of low-metallicity dwarf galaxies or the theoretically predicted smooth accretion of cold (∼ 10 4 K) gas are both potential drivers behind that process. Because the metallicity of the gas in the QSO narrow-line region is much lower than expected, we suspect that the external gas has already reached the galaxy centre and may even contribute to the current feeding of the black hole. HE 2158−0107 appears to represent a particular phase of substantial black hole and galaxy growth that can be observationally linked with the accretion of external material from its environment.

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Active Galactic Nucleus Emission‐Line Properties Versus the Eddington Ratio

Cited by 108 publications

References 79 publications

PRIMUS: AN OBSERVATIONALLY MOTIVATED MODEL TO CONNECT THE EVOLUTION OF THE ACTIVE GALACTIC NUCLEUS AND GALAXY POPULATIONS OUT TOz∼ 1

PRIMUS: AN OBSERVATIONALLY MOTIVATED MODEL TO CONNECT THE EVOLUTION OF THE ACTIVE GALACTIC NUCLEUS AND GALAXY POPULATIONS OUT TOz∼ 1

Near-infrared spectroscopy of a nitrogen-loud quasar SDSS J1707+6443

The low-metallicity QSO HE 2158 − 0107: a massive galaxy growing by accretion of nearly pristine gas from its environment?

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