Evidence for an outflow from the Seyfert galaxy NGC

Christopoulou, P. E.; Holloway, A. J.; Steffen, W.; Mundell, C. G.; Thean, Andrew; Goudis, C.; Meaburn, J.; Pedlar, A.

doi:10.1093/mnras/284.2.385

Cited by 65 publications

(82 citation statements)

References 26 publications

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“…This was also confirmed by the Chandra ACIS-S images of the same galaxy (Uttley et al 1999), which showed a size of the diffuse emission smaller than that of the optical narrow-line regions (30-220 pc, Christopoulou et al 1997), thus implying a clear separation between the X-ray and optical emissions. This is also naturally expected as a consequence of projection effects: as shown by Schmitt et al (2003), who studied a sample of 60 Seyfert galaxies with the Hubble Space Telescope, the Seyfert 1 narrow-line regions objects are more circular and compact than those in the Seyfert 2 galaxies, with the Seyfert 2 subsample characterized by more elongated shapes.…”

Section: Discussionsupporting

confidence: 62%

A characterization of the NGC 4051 soft X-ray spectrum as observed byXMM-Newton

Nucita¹,

Guainazzi²,

Longinotti³

et al. 2010

A&A

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Context. Soft X-ray high resolution spectroscopy of obscured AGNs shows a complex soft X-ray spectrum dominated by emission lines of He and H-like transitions of elements from carbon to neon, as well as L-shell transitions due to iron ions. Aims. In this paper we characterize the XMM-Newton RGS spectrum of the Seyfert 1 galaxy NGC 4051 observed during a low flux state and infer the physical properties of the emitting and absorbing gas in the soft X-ray regime. Methods. X-ray high-resolution spectroscopy offers a powerful diagnostic tool because the observed spectral features strongly depend on the physical properties of matter (ionization parameter U, electron density n e , hydrogen column density N H ), which in turn are tightly related to the location and size of the X-ray emitting clouds. We carried out a phenomenological study to identify the atomic transitions detected in the spectra. This study suggests that the spectrum is dominated by emission from a photoionized plasma. Then we used the photoionization code Cloudy to produce synthetic models for the emission line component and the warm absorber observed during phases of high intrinsic luminosity. Results. The low state spectrum cannot be described by a single photoionization component. A multi-ionization phase gas with an ionization parameter in the range of log U ∼ 0.63−1.90 and a column density log N H = 22.10−22.72 cm −2 is required, while the electron density n e remains unconstrained. A warm absorber medium is required by the fit with the parameters log U ∼ 0.85, log N H = 23.40 and log n e < ∼ 5. The model is consistent with an X-ray emitting region at a distance > ∼ 5 × 10 −2 pc from the central engine.

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Section: Discussionsupporting

confidence: 62%

A characterization of the NGC 4051 soft X-ray spectrum as observed byXMM-Newton

Nucita¹,

Guainazzi²,

Longinotti³

et al. 2010

A&A

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“…Peterson et al (2000) found that the Balmer lines could arise in a disk-like configuration and the high-ionization lines in an outflowing wind, of which we observe preferentially the near side. The structure and the kinematics of the [O III] lines also suggest an outflow (Christopoulou et al 1997 The X-ray source is variable by at least a factor 30 (Papadakis & Lawrence 1995;Leighly 1999a;Uttley et al 1999;Komossa & Meerschweinchen 2000); long term variations in the average X-ray flux might in principle be caused by absorption by a varying column of material along the line of sight; but this is ruled out by the spectral data; it is the 2-10 keV luminosity which shows large amplitude long-term variations (Uttley et al 1999).…”

Section: Mark 705 (0923+12)mentioning

confidence: 95%

A spectrophotometric atlas of Narrow-Line Seyfert 1 galaxies

Véron-Cetty

Véron

Gonçalves³

2001

A&A

285

324

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Abstract.We have compiled a list of 83 objects classified as Narrow-Line Seyfert 1 galaxies (NLS1s) or known to have a broad Balmer component narrower than 2 000 km s −1 . Of these, 19 turned out to have been spectroscopically misidentified in previous studies; only 64 of the selected objects are genuine NLS1s. We have spectroscopically observed 59 of them and tried to characterize their Narrow and Broad-Line Regions (NLR and BLR) by fitting the emission-lines with Gaussian and/or Lorentzian profiles. In most cases, the broad Balmer components are well fitted by a single Lorentzian profile, confirming previous claims that Lorentzian rather than Gaussian profiles are better suited to reproduce the shape of the NLS1s broad emission lines. This has consequences concerning their FWHMs and line ratios: when the broad Balmer components are fitted with a Lorentzian, most narrow line regions have line ratios typical of Seyfert 2s while, when a Gaussian profile is used for fitting the broad Balmer components, the line ratios are widely scattered in the usual diagnostic diagrams (Veilleux & Osterbrock 1987); moreover, the FWHM of the best fitting Lorentzian is systematically smaller than the FWHM of the Gaussian. We find that, in general, the [O III] lines have a relatively narrow Gaussian profile (∼200-500 km s −1 FWHM) with often, in addition, a second broad (∼500-1 800 km s −1 FWHM), blueshifted Gaussian component. We do not confirm that the [O III] lines are weak in NLS1s. As previously suggested, there is a continuous transition of all properties between NLS1s and classical Broad-Line Seyfert 1 Galaxies (BLS1s) and the limit of 2000 km s −1 used to separate the two species is arbitrary; R4570, the ratio of the Fe II to the Hβ fluxes, could be a physically more meaningful parameter to distinguish them.

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“…It has been known for a long time that the line profiles of the [O iii] doublets show a blue asymmetry with an extended blue wing and a sharp red falloff in a large fraction of AGNs (e.g., Heckman 1981;Whittle 1985;Wilson & Heckman 1985;Grupe et al 1999;Tadhunter et al 2001;Véron-Cetty et al 2001;Zamanov et al 2002;Xu & Komossa 2009;Greene & Ho 2005;de Robertis & Osterbrock 1984;Storchi-Bergmann et al 1992;Arribas et al 1996;Christopoulou et al 1997). The blue asymmetry requires a narrow core Gaussian profile (FWHM ∼ 200-500 km s −1 ) with a blueshifted, broad Gaussian component (FWHM ∼ 500-1000 km s −1 ) to reproduce the observed asymmetric profiles for both [O iii] λλ4959, 5007 emission lines.…”

Section: Introductionmentioning

confidence: 99%

Evolution of [O Iii] Λ5007 Emission-Line Profiles in Narrow Emission-Line Galaxies

Wang

Mao

Wei

2011

ApJ

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The active galactic nucleus (AGN)-host co-evolution issue is investigated here by focusing on the evolution of the [O iii] λ5007 emission-line profile. A large sample of narrow emission-line galaxies is selected from the Max-Planck Institute for Astrophysics/Johns Hopkins University Sloan Digital Sky Survey DR7 catalog to simultaneously measure both the [O iii] line profile and circumnuclear stellar population in an individual spectrum. By requiring that (1) the [O iii] line signal-to-noise ratio is larger than 30 and (2) the [O iii] line width is larger than the instrumental resolution by a factor of two, our sample is narrowed down to 2333 Seyfert galaxies/LINERs (AGNs), 793 transition galaxies, and 190 star-forming galaxies. In addition to the commonly used profile parameters (i.e., line centroid, relative velocity shift, and velocity dispersion), two dimensionless shape parameters, skewness and kurtosis, are used to quantify the line shape deviation from a pure Gaussian function. We show that the transition galaxies are systematically associated with narrower line widths and weaker [O iii] broad wings than the AGNs, which implies that the kinematics of emission-line gas are different in the two kinds of objects. By combining the measured host properties and line shape parameters, we find that the AGNs with stronger blue asymmetries tend to be associated with younger stellar populations. However, a similar trend is not identified in the transition galaxies. The failure likely results from a selection effect in which the transition galaxies are systematically associated with younger stellar populations than the AGNs. The evolutionary significance revealed here suggests that both narrow-line region kinematics and outflow feedback in AGNs co-evolve with their host galaxies.

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Evidence for an outflow from the Seyfert galaxy NGC

Cited by 65 publications

References 26 publications

A characterization of the NGC 4051 soft X-ray spectrum as observed byXMM-Newton

A characterization of the NGC 4051 soft X-ray spectrum as observed byXMM-Newton

A spectrophotometric atlas of Narrow-Line Seyfert 1 galaxies

Evolution of [O Iii] Λ5007 Emission-Line Profiles in Narrow Emission-Line Galaxies

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