Anisotropic radio and optical emission in the Seyfert nucleus of NGC 3227

Mundell, C. G.; Holloway, A. J.; Pedlar, A.; Meaburn, J.; Kukula, M. J.; Axon, D. J.

doi:10.1093/mnras/275.1.67

Cited by 65 publications

(105 citation statements)

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“…The most straightforward interpretation for the extended H 2 emission is that it lies in a 100 pc diameter 'disk' with a major axis PA ∼ 100 • . This 'disk' is not aligned with the ionization cone observed in [OIII] at PA ∼ 30 • or that of the 18cm radio emission at PA ∼ −10 • (Mundell et al 1995). The position angle of the H 2 emission also differs from that of the major axis of the galaxy (PA ∼ 155 • ).…”

Section: Ngc 3227mentioning

confidence: 68%

“…The morphology of the H 2 emission in both cases is most easily interpreted as emission from a 'disk' of 100 and 800 pc diameter in NGC 3227 and in NGC 2992 respectively. In both galaxies line emission from ionized gas and 6cm radio emission (Wehrle & Morris 1988, Mundell et al 1995 are observed along a different axis than the H 2 emission. Because this emission is associated with high levels of extinction, and not clearly associated with either the ionization cones or radio jets, it is unlikely that shocks or ionization associated with the jets and ionization cones can directly cause the excitation.…”

Section: H 2 Emission In a Dense 'Disk'mentioning

confidence: 91%

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NICMOS Imaging of Molecular Hydrogen Emission in Seyfert Galaxies

Quillen

Alonso‐Herrero

Rieke

et al. 1999

ApJ

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We present NICMOS imaging of broad band and molecular hydrogen emission in Seyfert galaxies. In 6/10 Seyferts we detect resolved or extended emission in the 1-0 S(1)λ2.121µm or 1-0 S(3)λ1.9570µm molecular hydrogen lines. We did not detect emission in the most distant galaxy or in the 2 Seyfert 1 galaxies in our sample because of the luminosity of the nuclear point sources. In NGC 5643, NGC 2110 and MKN 1066, molecular hydrogen emission is detected in the extended narrow line region on scales of a few hundred pc from the nucleus. Emission is coincident with [OIII] and Hα+ [NII] line emission. This emission is also near dust lanes observed in the visible to near-infrared color maps suggesting that a multiphase medium exists near the ionization cones and that the morphology of the line emission is dependent on the density of the ambient media. The high 1-0 S(1) or S(3) H 2 to Hα flux ratio suggests that shock excitation of molecular hydrogen (rather than UV fluorescence) is the dominant excitation process in these extended features. In NGC 2992 and NGC 3227 the molecular hydrogen emission is from 800 and 100 pc diameter 'disks' (respectively) which are not directly associated with [OIII] emission and are near high levels of extinction (A V ∼ > 10). In NGC 4945 the molecular hydrogen emission appears to be from the edge of a 100 pc superbubble. In these 3 galaxies the molecular gas could be excited by processes associated with local star formation. We confirm previous spectroscopic studies finding that no single mechanism is likely to be responsible for the molecular hydrogen excitation in Seyfert galaxies.

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Section: Ngc 3227mentioning

confidence: 68%

Section: H 2 Emission In a Dense 'Disk'mentioning

confidence: 91%

NICMOS Imaging of Molecular Hydrogen Emission in Seyfert Galaxies

Quillen

Alonso‐Herrero

Rieke

et al. 1999

ApJ

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“…In contrast we observe different weighted averages between the B-band (PA ∼ 140 • ) and R-band (PA ∼ 119 • ). Mundell et al (1995a) find both signatures for a narrow line region in highexcitation O  emission lines (PA ∼ 30 • ) and two compact radio cores along a PA of ∼170 • . Mundell et al (1995b) identify a much more extended radio source with PA ∼ 158 • , which shows a rotating disk-like structure on scales of a typical host galaxy with an inclination of ∼56 • ; any connection to the AGN on much smaller scales is not immediately obvious, especially given the uncertainty regarding the AGN system inclination.…”

Section: Optical Polarimetrymentioning

confidence: 89%

A variable-density absorption event in NGC 3227 mapped withSuzakuandSwift

Markowitz

Krauß

Miniutti

et al. 2015

A&A

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Context. The morphology of the circumnuclear gas accreting onto supermassive black holes in Seyfert galaxies remains a topic of much debate. As the innermost regions of active galactic nuclei (AGN) are spatially unresolved, X-ray spectroscopy, and in particular line-of-sight absorption variability, is a key diagnostic to map out the distribution of gas. Aims. Observations of variable X-ray absorption in multiple Seyferts and over a wide range of timescales indicate the presence of clumps/clouds of gas within the circumnuclear material. Eclipse events by clumps transiting the line of sight allow us to explore the properties of the clumps over a wide range of radial distances from the optical/UV broad line region (BLR) to beyond the dust sublimation radius. Time-resolved absorption events have been extremely rare so far, but suggest a range of density profiles across Seyferts. We resolve a weeks-long absorption event in the Seyfert NGC 3227. Methods. We examine six Suzaku and 12 Swift observations from a 2008 campaign spanning five weeks. We use a model accounting for the complex spectral interplay of three absorbers with different levels of ionization. We perform time-resolved spectroscopy to discern the absorption variability behavior. We also examine the IR to X-ray spectral energy distribution (SED) to test for reddening by dust. Results. The 2008 absorption event is due to moderately-ionized (log ξ ∼ 1.2-1.4) gas covering 90% of the line of sight. We resolve the density profile to be highly irregular, in contrast to a previous symmetric and centrally-peaked event mapped with RXTE in the same object. The UV data do not show significant reddening, suggesting that the cloud is dust-free. Conclusions. The 2008 campaign has revealed a transit by a filamentary, moderately-ionized cloud of variable density that is likely located in the BLR, and possibly part of a disk wind.

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“…4 double sources (Mundell et al 1995). The 5.0 GHz VLA "D" array observations show the kpc-scale extended radio emission, which is interpreted as the emission from star-forming host galaxy disk .…”

Section: Appendix A: Notes On Individual Sourcesmentioning

confidence: 92%

Low-frequency radio observations of Seyfert galaxies: A test of the unification scheme

Singh

Shastri

Ishwara‐Chandra

et al. 2013

A&A

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Aims. We present low-frequency radio imaging and spectral properties of a well-defined sample of Seyfert galaxies using GMRT 240/610 MHz dual frequency observations. Radio spectra of Seyfert galaxies over 240 MHz to 5.0 GHz are investigated using 240 MHz, 610 MHz flux densities derived from GMRT, and 1.4 GHz and 5.0 GHz flux densities mainly from published VLA data. We test the predictions of Seyfert unification scheme by comparing the radio properties of Seyfert type 1s and type 2s. Methods. We chose a sample such that the two Seyferts subtypes have matched distributions in parameters that are independent of the orientation of AGN, obscuring torus, and the host galaxy. Our sample selection criteria allowed us to assume that the two Seyfert subtypes are intrinsically similar within the framework of the unification scheme. , consistent with the synchrotron emission from optically thin plasma. In our snapshot 240/610 MHz GMRT observations, most of the Seyfert galaxies primarily show an unresolved central radio component, except for a few sources in which faint kpc-scale extended emission is apparent at 610 MHz. Our results on the statistical comparison of the multifrequency radio properties of our sample Seyfert galaxies agree with the predictions of the Seyfert unification scheme.

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Anisotropic radio and optical emission in the Seyfert nucleus of NGC 3227

Cited by 65 publications

References 0 publications

NICMOS Imaging of Molecular Hydrogen Emission in Seyfert Galaxies

NICMOS Imaging of Molecular Hydrogen Emission in Seyfert Galaxies

A variable-density absorption event in NGC 3227 mapped withSuzakuandSwift

Low-frequency radio observations of Seyfert galaxies: A test of the unification scheme

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