Near-ultraviolet spectroscopy of Seyfert nuclei - Reddening and Bowen fluorescence

Malkan, Matthew A.

doi:10.1086/164718

Cited by 12 publications

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“…Detection of optical CLs in this objects has been reported by Malkan (1986) and Cruz‐González et al (1994). They found [Ne v ] and [Fe vii ], respectively, in the nucleus of this source.…”

Section: Resultsmentioning

confidence: 51%

Demystifying the coronal-line region of active galactic nuclei: spatially resolved spectroscopy with theHubble Space Telescope

Mazzalay¹,

Rodríguez-Ardila²,

Komossa³

2010

Monthly Notices of the Royal Astronomical Society

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We present an analysis of Space Telescope Imaging Spectrograph (STIS)/Hubble Space Telescope optical spectra of a sample of 10 Seyfert galaxies aimed at studying the structure and physical properties of the coronal-line region (CLR). The high spatial resolution provided by STIS allowed us to resolve the CLR and obtain key information about the kinematics of the CL gas, measure directly its spatial scale, and study the mechanisms that drive the high-ionization lines. We find CLRs extending from just a few parsecs (∼10 pc) up to 230 pc in radius, consistent with the bulk of the coronal lines (CLs) originating between the broad-line region and narrow-line region (NLR), and extending into the NLR in the case of [Fe VII] and [Ne V] lines. The CL profiles strongly vary with the distance to the nucleus. We observed line splitting in the core of some of the galaxies. Line peak shifts, both redshift and blueshift, typically reached 500 km s −1 , and even higher velocities (1000 km s −1 ) in some of the galaxies. In general, CLs follow the same pattern of rotation curves as low-ionization lines like [O III]. From a direct comparison between the radio and the CL emission we find that neither the strength nor the kinematics of the CLs scales in any obvious and strong way with the radio jets. Moreover, the similarity of the flux distributions and kinematics of the CLs and low-ionization lines, the low temperatures derived for the gas, and the success of photoionization models to reproduce, within a factor of a few, the observed line ratios, point towards photoionization as the main driving mechanism of CLs.

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Section: Resultsmentioning

confidence: 51%

Demystifying the coronal-line region of active galactic nuclei: spatially resolved spectroscopy with theHubble Space Telescope

Mazzalay¹,

Rodríguez-Ardila²,

Komossa³

2010

Monthly Notices of the Royal Astronomical Society

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“…In contrast, the N H and the 2−10 keV flux values for bright nearby objects are more easily obtained either from published papers or from archival X-ray data. The main catalogs of optical/near-UV Seyfert spectra providing the [Ne V] fluxes used in this work are those published by Malkan (1986), Morris & Ward (1988), Storchi-Bergmann et al (1995), Erkens et al (1997), as well as the compilation by Schmitt (1998). A public catalog of HST/STIS spectra of nearby AGN has been released by Spinelli et al (2006).…”

Section: The Local Seyfert Samplementioning

confidence: 99%

“…[Ne V] references: (1) Anderson (1970); (2) Morris & Ward (1988); (3) Osterbrock & Pogge (1985); (4) Erkens et al (1997); (5) Malkan (1986); (6) Durret & Bergeron (1988); (7) Osterbrock et al (1976); (8) Winkler (1992); (9) Osterbrock (1981b); (10) Kunth et al (1987).…”

Section: A24 Ngc 1320mentioning

confidence: 99%

“…The measured 0.5−2 keV (2−10 keV) flux is ≈2.3 × 10 −13 erg cm −2 s −1 (≈5.7 × 10 −13 erg cm −2 s −1 ) 8 , and the de-absorbed, rest-frame 2−10 keV luminosity is ≈8.4 × 10 42 erg s −1 ; however, we note that this value is somehow uncertain, given the complex X-ray modeling of the data presented here. Koski (1978); (2) Anderson (1970); (3) Erkens et al 1997;(4) This work (based on the catalog of UV-optical spectra of nearby galaxies by Storchi-Bergmann et al, see text); (5) Durret & Bergeron (1988); (6) Durret & Bergeron (1986); (7) Shuder & Osterbrock (1981); (8) Morris & Ward (1988); (9) Shields & Filippenko (1990); (10) Ward et al (1980); (11) Malkan (1986); (12) Osterbrock (1981a); (13) Moran et al (1992); (14) Osterbrock & Miller (1975); (15) Fosbury & Sansom (1983).…”

Section: A24 Ngc 1320mentioning

confidence: 99%

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The X-ray to [Ne V]3426 flux ratio: discovering heavily obscured AGN in the distant Universe

Gilli¹,

Vignali

Mignoli³

et al. 2010

A&A

132

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We investigate the possibility of using the ratio between the 2−10 keV flux and the [Ne V]3426 emission line flux (X/NeV) as a diagnostic diagram to discover heavily obscured, possibly Compton-thick active galactic nuclei (AGN) in the distant Universe. While it is on average about one order of magnitude fainter than the more commonly used [O III]5007 emission line, the [Ne V]3426 line can be observed with optical spectroscopy up to z ∼ 1.5, whereas the [O III]5007 line is redshifted out of the optical bands already at z ∼ 0.8. First, we calibrated a relation between X/NeV and the cold absorbing column density N H using a sample of 74 bright, nearby Seyferts with both X-ray and [Ne V] data available in the literature and for which the column density is determined unambiguously. . Based on the X/NeV ratio, complemented by X-ray spectral analysis, 2 objects appear good Compton-thick QSO candidates, 4 objects appear as Compton-thin QSOs, while 3 have an ambiguous classification. When excluding broad-lined QSOs with a red continuum from the sample and thus considering only genuine narrow-line objects, the efficiency in selecting Compton-thick QSOs through the [Ne V] line is about 50% (with large errors, though), more similar to what is achieved with [O III] selection. We discuss the possibility of applying the X/NeV diagnostic to deep X-ray surveys to search for Compton-thick Seyferts at z ∼ 1, i.e., those objects that are thought to be responsible for the "missing" X-ray background. Finally, we compared the optical spectral properties of [Ne V]-selected QSOs with those of other SDSS populations of obscured and unobscured QSOs. By restricting the analysis to objects in the same redshift (and luminosity) range z = [0.4−1.5], we found evidence that, at any given [Ne V] luminosity, increasing obscuration is accompanied by increasing [O II]3727 emission. This correlation is interpreted as evidence of enhanced star formation in obscured QSOs, which is consistent with current popular scenarios of BH-galaxy coevolution.

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“…The observed line spectrum is taken from Malkan (1986 , Table 1). A typing error crept in the published data has been corrected (Hβ= 31. and not 3.1, M. Malkan, private communication).…”

Section: The Optical -Near-uv Line Spectrummentioning

confidence: 99%

A Multicloud Warm‐Absorber Model for NGC 4051

Contini

Viegas²

1999

ApJ

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A multi-cloud model is presented which explains the soft X-ray excess in NGC 4051 and, consistently, the optical line spectrum and the SED of the continuum. The clouds are heated and ionized by the photoionizing flux from the active center and by shocks. Diffuse radiation, partly absorbed throughout the clouds, nicely fits the bump in the soft X-ray domain, while bremsstrahlung radiation from the gaseous clouds contribute to the fit of the continuum SED. Debris of high density fragmented clouds are necessary to explain the absorption oxygen throats observed at 0.87 and 0.74 keV. The debris are heated by shocks of about 200-300 km s −1 . Low velocity (≤ 100 km s −1 ) -density (100 cm −3 ) clouds contribute to the line and continuum spectra, as well as high velocity (1000 km s −1 ) -density (8000 cm −3 ) clouds which are revealed by the FWHM of the line profiles. The SED in the IR is explained by reradiation of dust, however, the dust-to-gas ratio is not particularly high (≤ 3 × 10 −15 ). Radio emission is well fitted by synchrotron radiation created at the shock front by Fermi mechanism.

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Near-ultraviolet spectroscopy of Seyfert nuclei - Reddening and Bowen fluorescence

Cited by 12 publications

References 0 publications

Demystifying the coronal-line region of active galactic nuclei: spatially resolved spectroscopy with theHubble Space Telescope

Demystifying the coronal-line region of active galactic nuclei: spatially resolved spectroscopy with theHubble Space Telescope

The X-ray to [Ne V]3426 flux ratio: discovering heavily obscured AGN in the distant Universe

A Multicloud Warm‐Absorber Model for NGC 4051

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