The 1 Micron Fe<scp>ii</scp>Lines of the Seyfert Galaxy I Zw 1

Rudy, R. J.; Mazuk, S.; Puetter, R. C.; Hamann, Fred

doi:10.1086/309222

Cited by 46 publications

(66 citation statements)

References 39 publications

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“…Collin & Joly 2000). Observationally, these lines have been previously detected in only six extragalactic objects, all NLSy1s: I Zwicky 1 (Rudy et al 2000), Mrk 478 (Rudy et al 2001), 1H 1934, Ark 564, Mrk 335, and Mrk 1044(Rodríguez-Ardila et al 2002. Detailed discussions on the origin of the lines can be found in these papers.…”

Section: Resultsmentioning

confidence: 92%

NGC 5506 unmasked as a Narrow Line Seyfert 1:

Nagar

Oliva

Marconi

et al. 2002

A&A

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Abstract. This letter presents incontrovertible evidence that NGC 5506 is a Narrow Line Seyfert 1 (NLSy1). Our new 0.9-1.4 µm spectrum of its nucleus clearly shows the permitted O I λ1.1287 µm line (with full width at half maximum <2000 km s −1 ) and the "1 micron Fe II lines". These lines can only originate in the optically-thick broad line region (BLR) and, among Seyfert nuclei the latter series of lines are seen only in NLSy1s. The obscuration to the BLR, derived from a rough estimate of the O I λ1.1287 µm/O I λ8446 ratio and from the reddening of the near-IR Paschen lines, is A V > 5. Together, these results make NGC 5506 the first identified case of an optically-obscured NLSy1. This new classification helps explain its radio to X-ray properties, which until now were considered highly anomalous. However, interesting new concerns are raised: e.g., NGC 5506 is unusual in hosting both a "type 1" AGN and a nuclear water vapor megamaser. As the brightest known NLSy1, NGC 5506 is highly suitable for study at wavebands less affected by obscuration.

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Section: Resultsmentioning

confidence: 92%

NGC 5506 unmasked as a Narrow Line Seyfert 1:

Nagar

Oliva

Marconi

et al. 2002

A&A

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“…This reddening is that inferred from the COBE IR maps and is as given in NASA's Extragalactic Database ( NED). There may be other internal extinction intrinsic to I Zw 1 (see also Laor et al 1997;Rudy et al 2000). We discuss further the limits on any intrinsic dust in I Zw 1 in x 4.5.…”

Section: Dereddening the Spectrum Correcting For Galactic Extinctionmentioning

confidence: 88%

“…Our BLR fit to the Fe ii 2100Y 3050 8 emission does not require any intrinsic extinction due to dust. It must be mentioned that Rudy et al (2000), based on the observed intensities of O i k1304 and O i k8446, deduce an additional reddening of E(B À V ) ¼ 0:13 beyond that necessary from Galactic extinction. This assumes a Savage & Mathis (1979) extinction law.…”

Section: Lower Density Component As Revealed Through the Fe II Emissionmentioning

confidence: 99%

Modeling FeiiEmission and Revised Feii(UV) Empirical Templates for the Seyfert 1 Galaxy I Zw 1

Bruhweiler

Verner

2008

ApJ

125

173

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We use the narrow-lined broad-line region ( BLR) of the Seyfert 1 galaxy, I Zw 1, as a laboratory for modeling the ultraviolet (UV ) Fe ii 2100Y3050 8 emission complex. We calculate a grid of Fe ii emission spectra representative of BLR clouds and compare them with the observed I Zw 1 spectrum. Our predicted spectrum for log n H /(cm À3 ) ½ ¼ 11:0, log È H /(cm À2 s À1 ) ½ ¼ 20:5, and /(1 km s À1 ) ¼ 20, using Cloudy and an 830 level model atom for Fe ii with energies up to 14.06 eV, gives a better fit to the UV Fe ii emission than models with fewer levels. Our analysis indicates (1) the observed UV Fe ii emission must be corrected for an underlying Fe ii pseudocontinuum; (2) Fe ii emission peaks can be misidentified as that of other ions in active galactic nuclei (AGNs) with narrow-lined BLRs possibly affecting deduced physical parameters; (3) the shape of 4200Y4700 8 Fe ii emission in I Zw 1 and other AGNs is a relative indicator of narrow-line region ( NLR) and BLR Fe ii emission; (4) predicted ratios of Ly , C iii], and Fe ii emission relative to Mg ii k2800 agree with extinction corrected observed I Zw 1 fluxes, except for C iv k1549; (5) the sensitivity of Fe ii emission strength to microturbulence casts doubt on existing relative Fe/ Mg abundances derived from Fe ii (UV)/Mg ii flux ratios. Our calculated Fe ii emission spectra, suitable for BLRs in AGNs, are available at

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“…The ultraviolet spectra of active galactic nuclei (AGNs) with broad-line regions (BLRs) exhibit a quasi-continuum of thousands of blended iron emission lines, dominated by Fe ii (Wills et al 1980a(Wills et al , 1980b; numerous Fe ii transitions are also present in the optical (Boroson & Green 1992;Véron-Cetty et al 2004) and near-infrared (Rudy et al 2000(Rudy et al , 2001Rodríguez-Ardila et al 2002). Since their recognition as a significant component of the BLR emission spectrum, these Fe ii transitions have been the subject of intense observational scrutiny and theoretical modeling (Netzer 1980(Netzer , 1990Kwan & Krolik 1981;Netzer & Wills 1983;Wills et al 1985;Elitzur & Netzer 1985;Collin-Souffrin et al 1986, 1988Penston 1987;Dumont & Collin-Souffrin 1990;Sigut & Pradhan 1998, 2003Verner et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Theoretical Fei–iiiEmission‐Line Strengths from Active Galactic Nuclei with Broad‐Line Regions

Sigut

Pradhan

Nahar

2004

ApJ

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We present theoretical iron emission line strengths for physical conditions typical of active galactic nuclei (AGNs) with broad-line regions. The non-local thermodynamic equilibrium (NLTE) models include a new and extensive treatment of radiative transfer in the Fe iii ion, complementing the Fe ii emission line strengths predicted in our earlier works. We also briefly present preliminary results for the Fe i emission from AGNs using a reduced atom model. We can satisfactorily reproduce the empirical UV Fe iii emission line template of Vestergaard & Wilkes for the prototypical narrow-line Seyfert 1 galaxy I Zw 1, both in terms of the general Fe iii flux distribution and the relative strength of the Fe iii and Fe ii emission. However, a number of detailed features are still not matched; the most prominent example is the strongest single Fe iii feature observed in the I Zw 1 spectrum, UV47: it is predicted to be strong only in models suppressing Fe-H charge exchange reactions. We examine the role of variations in cloud turbulent velocity and iron abundance and carry out Monte Carlo simulations to demonstrate the effect of uncertainties in atomic data on the computed spectra.

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The 1 Micron FeiiLines of the Seyfert Galaxy I Zw 1

Cited by 46 publications

References 39 publications

NGC 5506 unmasked as a Narrow Line Seyfert 1:

NGC 5506 unmasked as a Narrow Line Seyfert 1:

Modeling FeiiEmission and Revised Feii(UV) Empirical Templates for the Seyfert 1 Galaxy I Zw 1

Theoretical Fei–iiiEmission‐Line Strengths from Active Galactic Nuclei with Broad‐Line Regions

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