C<scp>iv</scp>λ1549 as an Eigenvector 1 Parameter for Active Galactic Nuclei

Sulentic, J. W.; Bachev, R.; Marziani, Paola; Negrete, C. A.; Dultzin, D.

doi:10.1086/519916

Cited by 246 publications

(486 citation statements)

References 73 publications

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“…Within the observed wavelength range we obtained several lines (from Lyα to Ciii]λ1909) from which diagnostics intensity ratios can be computed. The GTC spectra are similar to or better than the HST archival UV spectra for low-redshift analogs (Bachev et al 2004;Sulentic et al 2007). Figure 3 shows a montage of the deredshifted GTC spectra obtained for 22 quasars.…”

Section: Observations and Data Reductionmentioning

confidence: 64%

“…Spectra show an S/N near 10-20, covering Lyα -Ciii]λ1909 in the rest frame. They can be effectively compared with low-z UV spectra from the HST archive that were previously studied in the 4DE1 context (Bachev et al 2004;Sulentic et al 2007). Our high-z sample clusters near log L bol ∼ 46.0 with redshift range from z = 2.21−2.40.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

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GTC spectra ofz≈ 2.3 quasars: comparison with local luminosity analogs

Sulentic¹,

Marziani²,

Olmo³

et al. 2014

A&A

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Context. The advent of 8−10 m class telescopes for the first time makes it possible to compare in detail quasars with similar luminosity and very different redshifts. Aims. We conducted a search for z-dependent gradients in line-emission diagnostics and derived physical properties by comparing, in a narrow bolometric luminosity range (log L ∼ 46.1± 0.4 [erg s −1 ]), some of the most luminous local z < 0.6 quasars with some of the lowest luminosity sources yet found at redshift z = 2.1−2.5. Methods. Moderate signal-to-noise ratio spectra for 22 high-redshift sources were obtained with the 10.4 m Gran Telescopio Canarias (GTC), for which the HST (largely the Faint Object Spectrograph) archive provides a low-redshift control sample. We compared the spectra in the context of the 4D Eigenvector 1 formalism, meaning that we divided both source samples into highly accreting population A and population B sources accreting at a lower rate. Results. Civλ1549, the strongest and most reliable diagnostic line, shows very similar properties at both redshifts, which confirms the Civλ1549 profile differences at high redshift between populations A and B, which are well established in local quasars. The Civλ1549 blueshift that appears quasi-ubiquitous in higher L sources is found in only half (population A) of the quasars observed in the two samples. A Civλ1549 evolutionary Baldwin effect is certainly disfavored. We find evidence for lower metallicity in the GTC sample that may point toward a gradient with z. No evidence for a gradient in M BH or L/L Edd is found. Conclusions. Spectroscopic differences established at low z are also present in much higher redshift quasars. Our results on the Civλ1549 blueshift suggest that it depends both on source luminosity and L/L Edd . Given that our samples involve sources with very similar luminosity, the evidence for a systematic metallicity decrease, if real, points toward an evolutionary effect. Our samples are not large enough to effectively constrain possible changes of M BH or L/L Edd with redshift. The two samples appear representative of a slowly evolving quasar population that is most likely present at all redshifts.

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Section: Observations and Data Reductionmentioning

confidence: 64%

Section: Observations and Data Reductionmentioning

confidence: 99%

GTC spectra ofz≈ 2.3 quasars: comparison with local luminosity analogs

Sulentic¹,

Marziani²,

Olmo³

et al. 2014

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…Civλ1549 also shows a blueshift and profile asymmetry in many sources (Gaskell 1982;Brotherton 1996;Sulentic et al 2007;Richards et al 2011), which challenges the validity of the virial assumption. Some consistency can be achieved if several cautions and corrections are applied to the Civλ1549 measures (Assef et al 2011;Denney 2012;Greene et al 2010, and especially in the 4DE1 context as done by Sulentic et al 2007), but this is not the road to M BH estimates with uncertainties less than 1 dex. In the 4DE1 context (Sulentic et al 2000b) both Hβ and Civλ1549 show strikingly different profile properties for Pop.…”

Section: Introductionmentioning

confidence: 99%

“…Interpreting of quasar spectra in the context of a 4D parameter space stemming from eigenvector studies reveals a wide diversity of line profile properties (Sulentic et al 2000a(Sulentic et al , 2007Marziani et al 2003bMarziani et al , 2010 that are most likely driven by L/L Edd , with M BH and source orientation also playing important roles (Boroson & Green 1992;Marziani et al 2001;Yip et al 2004). The 4DE1 (4D eigenvector 1) formalism owes its Now at Instituto de Astronomía, UNAM, Ensenada Campus, Baja California, México. inception to a principal component analysis study of systematic trends in quasar spectra (Boroson & Green 1992) from the the Palomar-Green (PG) survey.…”

Section: Introductionmentioning

confidence: 99%

“…Civλ1549 is not recommended as a virial estimator because FWHM Civλ1549 does not even show a correlation with FWHM Hβ (Marziani et al 1996;Sulentic et al 2007;Netzer et al 2007;Shen et al 2008;Richards et al 2011). Civλ1549 also shows a blueshift and profile asymmetry in many sources (Gaskell 1982;Brotherton 1996;Sulentic et al 2007;Richards et al 2011), which challenges the validity of the virial assumption. Some consistency can be achieved if several cautions and corrections are applied to the Civλ1549 measures (Assef et al 2011;Denney 2012;Greene et al 2010, and especially in the 4DE1 context as done by Sulentic et al 2007), but this is not the road to M BH estimates with uncertainties less than 1 dex.…”

Section: Introductionmentioning

confidence: 99%

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Is MgIIλ2800 a reliable virial broadening estimator for quasars?

Marziani

Sulentic

Plauchu-Frayn

et al. 2013

A&A

156

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Context. Broad Mgiiλ2800 and Hβ lines have emerged as the most reliable virial estimators of the black hole mass in quasars. Which is more reliable? Part of the challenge centers on comparing Mgiiλ2800 and Hβ line profiles in order to improve the ±1 dex M BH uncertainties inherent in single-epoch FWHM measures from noisy spectra. Aims. We compare Mgiiλ2800 and Hβ profile measures in the same sources and especially FWHM measures that provide the virial broadening estimator. Methods. We identify 680 bright Sloan Digital Sky Survey Data Release 7 quasars with spectra showing both Mgiiλ2800 and Hβ lines at redshift 0.4 ≤ z ≤ 0.75. The S/N of these spectra are high enough to allow binning in the "four-dimensional (4D) eigenvector 1" optical plane and construction of high S/N composite spectra. Results. We confirm that Mgiiλ2800 shows a profile that is ≈20% narrower as suggested in some previous studies. FWHM measures for Population B sources (i.e., with FWHM of Hβ larger than 4000 km s −1 ) are uncertain because they show complex profiles with at least two broad-line components involving a nearly unshifted broad and redshifted very-broad component. Only the broad component is likely to be a valid virial estimator. If Hβ and Mgiiλ2800 are not corrected for the very broad component then black hole mass M BH values for Population B sources will be systematically overestimated by up to Δ logM BH ≈ 0.3−0.4 dex. We suggest a simple correction that can be applied to the majority of sources. Mgiiλ2800 is the safer virial estimator for Population B sources because the centroid shifts with respect to rest frame are lower than for Hβ. In the broad and very broad component profile interpretation, this is a consequence of the lower very broad to broad component intensity ratio for Mgiiλ2800. Eigenvector-based studies show that effective discrimination of black hole mass and Eddington ratio at fixed redshift is not achieved via luminosity binning but rather by binning in a "4D eigenvector 1" context that reflects different broad line region geometry/kinematics probably driven by the Eddington ratio.

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The main sequence of quasars: The taming of the extremes

Marziani

Bon

et al. 2021

Astron Nachr

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The last few years have seen the confirmation of several trends associated with the quasar main sequence. The idea of a main sequence for quasars is relatively recent, and its full potential for the observational classification and contextualization of quasars' properties has yet to be fully exploited. The main sequence drivers are discussed in terms of the properties of extreme objects. We briefly summarize developments that constrain the viewing angle of the accretion disk in a particular class of quasars (extreme Population B, radiating at low Eddington ratio), as well as inferences on the chemical composition of the broad line emitting gas, and on the nature of radio emission along the quasar main sequence.

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Civλ1549 as an Eigenvector 1 Parameter for Active Galactic Nuclei

Cited by 246 publications

References 73 publications

GTC spectra ofz≈ 2.3 quasars: comparison with local luminosity analogs

GTC spectra ofz≈ 2.3 quasars: comparison with local luminosity analogs

Is MgIIλ2800 a reliable virial broadening estimator for quasars?

The main sequence of quasars: The taming of the extremes

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