Narrow-Line Seyfert 1s: a luminosity dependent definition

Dultzin, D.

doi:10.22323/1.126.0012

Cited by 5 publications

(5 citation statements)

References 17 publications

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“…Because they are hypothesized to be younger quasars, we might expect to find more of them at z ≈ 2.3. High-z analogs of I Zw 1 (albeit with a much higher luminosity) were identified in one of our companion surveys (Dultzin et al 2011;Negrete et al 2012;Marziani & Sulentic 2014a,b). Table 6 reports normalized fluxes and equivalent widths for population A and B composite spectra (average and median).…”

Section: Comparing Population a And B Uv Spectra At High And Low Redsmentioning

confidence: 75%

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: Comparing Population a And B Uv Spectra At High And Low Redsmentioning

confidence: 75%

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

Sulentic¹,

Marziani²,

Olmo³

et al. 2014

A&A

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“…4 adapted from [68]). In practice, for a limiting L/L Edd = 1 the increase in FWHM as a If we want to consider a physical definition of NLSy1s as sources radiating close to the Eddington limit, then it is necessary to generalize to broader line widths [29], employing a defining criterion that is independent of line width and instead traces the source accretion state.…”

Section: Highly Accreting Pop a Sourcesmentioning

confidence: 99%

Low- and High-zHighly Accreting Quasars in the 4D Eigenvector 1 Context

Marziani¹,

Sulentic²,

Negrete³

et al. 2014

Astronomical Review

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Highly accreting quasars are characterized by distinguishing properties in the 4D eigenvector 1 parameter space that make them easily recognizable over a broad range range of redshift and luminosity. The 4D eigenvector 1 approach allows us to define selection criteria that go beyond the restriction to Narrow Line Seyfert 1s identified at low redshift. These criteria are probably able to isolate sources with a defined physical structure i.e., a geometrically thick, optically thick advectiondominated accretion disk (a "slim" disk). We stress that the importance of highly accreting quasars goes beyond the understanding of the details of their physics: their Eddington ratio is expected to saturate toward values of order unity, making them possible cosmological probes.

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“…However for lower-M BH Sersic galaxies, following the relation found by Scott et al (2013), at M BH = 10 6 M , M BH ∼ 10 −4 M bulge [16]. 10 The other two sources: Mrk 1388 seems to be a high-ionization Seyfert 2 galaxy [26,15], and Mrk 684 presents broad Hβ and strong FeII emission, but its Eddington ratio L bol /L Edd ∼ 10 −7 is very unusual for a Type 1 source (M BH and L bol from [34,17], see spectrum in [32]).…”

Section: Final Commentsmentioning

confidence: 52%

“…To account for that, a luminositydependent definition of NLSy1 has been suggested several times (e.g. [21,33,10]). On the other hand, the broad line profiles are not all the same, one (or two) Gaussians (or Lorentzians) are required to model them [33,23].…”

Section: Pos(seyfert 2012)017mentioning

confidence: 99%

Are Narrow Line Seyfert 1 galaxies a special class of Active Galactic Nuclei?

Valencia-S.¹,

Zuther²,

Eckart³

et al. 2013

Proceedings of Nuclei of Seyfert Galaxies and QSOs - Central Engine &Amp; Conditions of Star Formation — PoS(Seyfert 2012)

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No. Due to their apparently extreme optical to X-ray properties, Narrow Line Seyfert 1s (NLSy1s) have been considered a special class of active galactic nuclei (AGN). Here, we summarize observational results from different groups to conclude that none of the characteristics that are typically used to define the NLSy1s as a distinct group-from the, nowadays called, Broad Line Seyfert 1s (BLSy1s)-is unique, nor ubiquitous of these particular sources, but shared by the whole Type 1 AGN. Historically, the NLSy1s have been distinguished from the BLSy1s by the narrow width of the broad Hβ emission line. The upper limit on the full width at half maximum of this line is 2000 km s −1 for NLSy1s, while in BLSy1s it can be of several thousands of km s −1. However, this border has been arbitrarily set and does not correspond to the change of any physical property. All observed parameters in Type 1 AGN cover continues ranges of values, which does not allow to infer the existence of two different kind of populations with FWHM Hβ ,broad = 2000 km s −1 as dividing point. We argue that the usage of this velocity limit to define samples of NLSy1s galaxies-as it is usually done in comparative studies-, together with the well known observational biases, naturally favors the selection of sources with low black hole masses and high Eddington ratios that are hosted by blue spiral galaxies. Therefore selection biases might be responsible for the reported differences between NLSy1 and BLSy1 sources.

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Narrow-Line Seyfert 1s: a luminosity dependent definition

Cited by 5 publications

References 17 publications

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

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

Low- and High-zHighly Accreting Quasars in the 4D Eigenvector 1 Context

Are Narrow Line Seyfert 1 galaxies a special class of Active Galactic Nuclei?

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