Studies of broad emission line profiles in QSOs – I. Observed, high-resolution profiles

Wilkes, Belinda

doi:10.1093/mnras/207.1.73

Cited by 95 publications

(75 citation statements)

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“…This concern arises from the typically blueshifted C iv BEL peak compared to other quasars BELs (Gaskell 1982;Richards et al 2002b, S11), the commonly observed BAL/NALs (Weymann et al 1981;Wild et al 2008) within the C iv emission line profiles, and the strong line asymmetries (Wilkes 1984;Richards et al 2002b, See also Section 3). The blueshift of the C iv BEL peak relative Mg ii is observed in ∼80% of the MIR-quasars whose spectra covers both C iv and Mg ii BELs.…”

Section: Discussionmentioning

confidence: 99%

Mid-Infrared-Selected Quasars. I. Virial Black Hole Mass and Eddington Ratios

Dai

Elvis

Bergeron

et al. 2014

ApJ

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We provide a catalog of 391 mid-infrared-selected (MIR; 24 μm) broad-emission-line (BEL; type 1) quasars in the 22 deg 2 SWIRE Lockman Hole field. This quasar sample is selected in the MIR from Spitzer MIPS with S 24 > 400 μJy, jointly with an optical magnitude limit of r (AB) < 22.5 for broad line identification. The catalog is based on MMT and Sloan Digital Sky Survey (SDSS) spectroscopy to select BEL quasars, extending the SDSS coverage to fainter magnitudes and lower redshifts, and recovers a more complete quasar population. The MIR-selected quasar sample peaks at z ∼ 1.4 and recovers a significant and constant (20%) fraction of extended objects with SDSS photometry across magnitudes, which were not included in the SDSS quasar survey dominated by point sources. This sample also recovers a significant population of z < 3 quasars at i > 19.1. We then investigate the continuum luminosity and line profiles of these MIR quasars, and estimate their virial black hole masses and the Eddington ratios. The supermassive black hole mass shows evidence of downsizing, although the Eddington ratios remain constant at 1 < z < 4. Compared to point sources in the same redshift range, extended sources at z < 1 show systematically lower Eddington ratios. The catalog and spectra are publicly available online.

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Section: Discussionmentioning

confidence: 99%

Mid-Infrared-Selected Quasars. I. Virial Black Hole Mass and Eddington Ratios

Dai

Elvis

Bergeron

et al. 2014

ApJ

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“…This is because those high-ionization lines are emitted from the closer region to the AGN central engine than low-ionization lines, such as Mg II, as suggested by reverberation mapping observations (e.g., Clavel et al 1991;Sulentic et al 2000;Wang et al 2012) and also by photoionization models (e.g., Baldwin et al 1995;Korista & Goad 2000). In fact, the C IV emission line sometimes show significant blueshifts (Gaskell 1982;Wilkes 1984;Marziani et al 1996;Sulentic et al 2000;Vanden Berk et al 2001;Richards et al 2002;Baskin & Laor 2005;Sulentic et al 2007) or asymmetric velocity profiles (Sulentic et al 2000;Baskin & Laor 2005;Sulentic et al 2007) than low-ionization BLR lines. It has been also reported that the outflow properties in BLRs are also related to the Eddington ratio (e.g., Wang et al 2011).…”

Section: Introductionmentioning

confidence: 93%

Outflow and Metallicity in the Broad-Line Region of Low-Redshift Active Galactic Nuclei

Shin

Nagao

Woo

2017

ApJ

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Outflows in active galactic nuclei (AGNs) are crucial to understand in investigating the co-evolution of supermassive black holes (SMBHs) and their host galaxies since outflows may play an important role as an AGN feedback mechanism. Based on the archival UV spectra obtained with HST and IUE, we investigate outflows in the broad-line region (BLR) in low-redshift AGNs (z < 0.4) through the detailed analysis of the velocity profile of the C IV emission line. We find a dependence of the outflow strength on the Eddington ratio and the BLR metallicity in our low-redshift AGN sample, which is consistent with the earlier results obtained for high-redshift quasars. These results suggest that the BLR outflows, gas accretion onto SMBH, and past starformation activity in the host galaxies are physically related in low-redshift AGNs as in powerful high-redshift quasars.

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“…26. The velocity difference between HILs and LILs has been analyzed for a long time to investigate various kinematic/geometrical models for BLRs (e.g., Gaskell 1982;Wilkes 1984Wilkes , 1986Espey et al 1989;Corbin 1990;Vanden Berk et al 2001). The correlation between this velocity difference and the quasar luminosity has been reported also by other studies (e.g., Corbin 1990;Richards et al 2002b).…”

Section: Comparison Of Observed Line Ratios and Trends With Modelsmentioning

confidence: 99%

The evolution of the broad-line region among SDSS quasars

Nagao

Marconi

Maiolino

2006

A&A

196

310

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Based on 5344 quasar spectra taken from the SDSS Data Release 2, the dependences of various emission-line flux ratios on redshift and quasar luminosity are investigated in the ranges 2.0 ≤ z ≤ 4.5 and −24.5 ≥ M B ≥ −29.5. We show that the emission lines in the composite spectra are fitted better with power-law profiles than with double Gaussian or modified Lorentzian profiles, and in particular we show that the power-law profiles are more appropriate to measure broad emission-line fluxes than other methods. The composite spectra show that there are statistically significant correlations between quasar luminosity and various emission-line flux ratios, such as Nv/Civ and Nv/Heii, while there are only marginal correlations between quasar redshift and emission-line flux ratios. We obtain detailed photoionization models to interpret the observed line ratios. The correlation of line ratios with luminosity is interpreted in terms of higher gas metallicity in more luminous quasars. For a given quasar luminosity, there is no metallicity evolution for the redshift range 2.0 ≤ z ≤ 4.5. The typical metallicity of BLR gas clouds is estimated to be Z ∼ 5 Z , although the inferred metallicity depends on the assumed BLR cloud properties, such as their density distribution function and their radial distribution. The absence of a metallicity evolution up to z ∼ 4.5 implies that the active star-formation epoch of quasar host galaxies occurred at z > ∼ 7.

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Studies of broad emission line profiles in QSOs – I. Observed, high-resolution profiles

Cited by 95 publications

References 0 publications

Mid-Infrared-Selected Quasars. I. Virial Black Hole Mass and Eddington Ratios

Mid-Infrared-Selected Quasars. I. Virial Black Hole Mass and Eddington Ratios

Outflow and Metallicity in the Broad-Line Region of Low-Redshift Active Galactic Nuclei

The evolution of the broad-line region among SDSS quasars

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