NGC 7679: an anomalous, composite Seyfert 1 galaxy whose X-ray luminous AGN vanishes at optical wavelengths

Buson, L. M.; Cappellari, Michele; Corsini, E. M.; Held, E. V.; Lim, Jeremy; Pizzella, A.

doi:10.1051/0004-6361:20053204

Cited by 4 publications

(5 citation statements)

References 40 publications

(75 reference statements)

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“…This arc is not detected on the narrow-band continuum image next to the Hα. The same morphology in Hα + [N II] with higher spatial resolution was observed by Buson et al (2006).…”

Section: Narrow-band Emission-line Imagessupporting

confidence: 72%

“…In Fig. 2 we present our very deep and high-contrast Hα continuum-subtracted image with numerous starburst regions where because of both seeing and pixel size we are able to see only elliptical central isophotes instead of the "double nucleus" observed recently by Buson et al (2006). Our analysis of the unpublished Hα images taken from the archive of the Isaak Newton Group of telescopes at La Palma as well as the archive images of Buson et al (2006) from the ESO La Silla NTT also revealed a "double nucleus" otherwise unseen in the known broad-band images.…”

Section: Narrow-band Emission-line Imagesmentioning

confidence: 87%

“…Usually, the hydrogen line flux F(Hα ) or F(Hβ ) is used to find N ph . But the NGC 7679 high resolution Hα image reveals a central circumnuclear star-forming spiral ring capable of producing about ∼ 75% of the optical line emission within a radius of ∼ 1 kpc (Buson et al 2006). For this reason it is not quite correct to use the F(Hα) in order to make the N ph estimate.…”

Section: Physical Conditions In the Circumnuclear Region Of Ngc 7679mentioning

confidence: 99%

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The luminous infrared composite Seyfert 2 galaxy NGC 7679 through the [O III] λ 5007 emission line

Yankulova

Golev

Jockers³

2007

A&A

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Context. NGC 7679 (Mrk 534) is a nearby (z = 0.0177) nearly face-on SB0 luminous infrared Sy2 galaxy in which starburst and AGN activities co-exist. The ionization structure is maintained by both the AGN power-law continuum and starburst. The galaxy is a bright X-ray source possessing a low X-ray column density N H < 4 × 10 20 cm −2 . Aims. The Compton-thin nature of such unabsorbed objects infers that the simple formulation of the Unified model for SyGs is not applicable in their case. The absorption is likely to originate at larger scales instead of the pc-scale molecular torus. The main goal of this article is to investigate both gas distribution and ionization structure in the circumnuclear region of NGC 7679 in search for the presence of a hidden Sy1-type nucleus, using the [O III]λ5007 luminosity as a tracer of AGN activity. Methods. NGC 7679 was observed with the 2m RCC reflector of the Ukraine National Astronomical Observatory at peak Terskol, Caucasus, Russia. The observations were carried out in October 1996 with the Focal Reducer of the Max-Planck-Institut für Sonnensystemforschung, Germany. All observations were taken with tunable Fabry-Perot narrow-band imaging with spectral FWHM of the Airy profile δλ between 3 and 4 Å depending on the used wavelength. Results. The [O III]λ5007 emission-line image of the circumnuclear region of NGC 7679 shows elliptical isophotes extended along the PA ≈ 80• in the direction of the counterpart galaxy NGC 7682. There is a maximum of this emission which is shifted ∼4 arcsec from the center as defined by the continuum emission. The maximum of ionization by the AGN power-law continuum traced by [O III]λ5007/Hα ratio is displaced by ∼13 arcsec eastward from the nucleus. The direction where high ionization is observed at PA ≈ 80• ± 10• coincides with the direction to the companion galaxy NGC 7682 (PA ≈ 72 • ). On the contrary, at PA ∼ 0 • the ionization in the circumnuclear region is entirely due to hot stars.

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“…This arc is not detected on the narrow-band continuum image next to the Hα. The same morphology in Hα + [N II] with higher spatial resolution was observed by Buson et al (2006).…”

Section: Narrow-band Emission-line Imagessupporting

confidence: 72%

Section: Narrow-band Emission-line Imagesmentioning

confidence: 87%

Section: Physical Conditions In the Circumnuclear Region Of Ngc 7679mentioning

confidence: 99%

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The luminous infrared composite Seyfert 2 galaxy NGC 7679 through the [O III] λ 5007 emission line

Yankulova

Golev

Jockers³

2007

A&A

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“…The inclination of the model map with the minimum χ 2 was recognized as the global estimate of the inclination of the observed disc. An almost identical procedure (they varied both PA and i simultaneously) was used previously by Buson et al (2006).…”

Section: Kinematical Properties Of the Nuclear Discmentioning

confidence: 99%

Integral-field spectroscopy of Centaurus A nucleus

Krajnović

Sharp

Thatte

2007

Monthly Notices of the Royal Astronomical Society

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[abridged] We report integral-field spectroscopic observations with CIRPASS mounted on the GEMINI South telescope of the nucleus of the nearby galaxy NGC 5128 (Centaurus A). We detect two-dimensional distributions of the following emission-lines: [PII], [FeII] and Paschen beta. We compare our observations with previously published radio observations (VLA) and archival space-based near-infrared imaging (HST/NICMOS) and find similar features, as well as a region of high continuum coinciding with the jet (and its N1 knot) at about 2 arcsec North-East of the nucleus, possibly related to jet-induced star formation. We use the [FeII]/[PII] ratio to probe the ionisation mechanism, which suggests that with increasing radius shocks play an increasingly important role. We extract spatially resolved 2D kinematics of Pa beta and [FeII] emission-lines. All emission-line regions are part of the same kinematic structure which shows a twist in the zero-velocity curve beyond ~1 arcsec (for both Pa beta and [FeII]). The kinematics of the two emission-lines are similar, but the Pa beta velocity gradient is steeper in the centre while the velocity dispersion is low everywhere. The velocity dispersion of the [FeII] emission is relatively high featuring a plateau, approximately oriented in the same way as the central part of the warped disk. We use 2D kinematic information to test the hypothesis that the ionised gas is distributed in a circularly rotating disk. We estimate the mass of the central black hole using Pa beta kinematics, which is consistent with being distributed in a circularly rotating disk. We obtain Mbh = 8.25^{+2.25}_{-4.25} * 10^7 Msun, for PA = -3 degr and i=25 degr, which is in good agreement with previous studies.Comment: 15 pages, 10 figures. Accepted for publication in MNRA

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“…The inclination of the model map with the minimum χ 2 was recognised as the global estimate of the inclination of the observed disk. An almost identical procedure (they varied both P A and i simultaneously) was used previously by Buson et al (2006).…”

Section: Orientation Of the Velocity Structuresmentioning

confidence: 99%

Integral-Field Spectroscopy of the Centaurus A Nucleus

Krajnović

Sharp

Thatte

2008

Astrophysics and Space Science Proceedings

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We report integral-field spectroscopic observations with the Cambridge Infra-Red Panoramic Survey Spectrograph (CIRPASS) mounted on the GEMINI South telescope of the nucleus of the nearby galaxy NGC 5128 (Centaurus A). We detect two-dimensional distributions of the following emission-lines: [PII], [FeII] and Paschen β. We compare our observations with previously published radio observations (VLA) and archival space-based near-infrared imaging (HST/NICMOS) and find similar features, as well as a region of high continuum coinciding with the jet (and its N1 knot) at about 2 ′′ North-East of the nucleus, possibly related to jetinduced star formation. We use the [FeII]/[PII] ratio to probe the ionisation mechanism, which suggests that with increasing radius shocks play an increasingly important role. We extract spatially resolved 2D kinematics of Paβ and [FeII] emission-lines. All emission-line regions are part of the same kinematic structure which shows a twist in the zero-velocity curve beyond ∼ 1 ′′ (for both Paβ and [FeII]). The kinematics of the two emission-lines are similar, but the Paβ velocity gradient is steeper in the centre while the velocity dispersion is low everywhere. The velocity dispersion of the [FeII] emission is relatively high featuring a plateau, approximately oriented in the same way as the central part of the warped disk. We use 2D kinematic information to test the hypothesis that the ionised gas is distributed in a circularly rotating disk. Assuming simple disk geometry we estimate the mass of the central black hole using Paβ kinematics, which is consistent with being distributed in a circularly rotating disk. We obtain M • = 8.25 +2.25−4.25 × 10 7 M ⊙ , for P A = −3• and i = 25• , excluding the M • − σ relation prediction at a 3σ confidence level, which is in good agreement with previous studies.

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NGC 7679: an anomalous, composite Seyfert 1 galaxy whose X-ray luminous AGN vanishes at optical wavelengths

Cited by 4 publications

References 40 publications

The luminous infrared composite Seyfert 2 galaxy NGC 7679 through the [O III] λ 5007 emission line

The luminous infrared composite Seyfert 2 galaxy NGC 7679 through the [O III] λ 5007 emission line

Integral-field spectroscopy of Centaurus A nucleus

Integral-Field Spectroscopy of the Centaurus A Nucleus

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