Interaction of Jets with Clouds in Extragalactic Radio Sources

Fedorenko, V. N.; Zentsova, A. S.; Courvoisier, T. J. L.; Paltani, S.

doi:10.1007/978-94-010-9537-2_72

Cited by 5 publications

(6 citation statements)

References 3 publications

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“…First, we note that the morphological and kinematic patterns do not support any of the idealized theoretical models most frequently discussed, at least in their pure form. These models include (1) an expanding plasmon compressing and shocking ambient gas (Pedlar, Dyson, & Unger 1985); (2) a jet-driven bow shock with line-emitting gas emerging within the postshock cooling region (e.g., Taylor et al 1992;Ferruit et al 1997;Bicknell, Dopita, & O'Dea 1997); (3) gas that is laterally entrained and accelerated along the jet length (e.g., Blandford & Konigl 1979;Bicknell 1986;Fedorenko, Paltani, & Zentsova 1996); and (4) gas that is driven away from the jet axis by an expanding cocoon (e.g., Steffen et al 1997;Lim & Steffen 2001). Although local versions of phenomena described in these models may well be occurring, the global pattern that they suggest is missing-the observed regions are simply too complex.…”

Section: Discussionmentioning

confidence: 99%

Jet-Gas Interactions in Markarian 78. I. Morphology and Kinematics

Whittle¹,

Wilson²

2004

Astron J

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We present a detailed study of the Seyfert 2 galaxy Markarian 78, using continuum and emission-line images and multiaperture spectra from the Hubble Space Telescope (HST) and a deep 3.6 cm VLA image. Our overall aim is to study the interaction between the radio source and the emission-line gas, since ground-based data already indicate the presence of a strong bipolar jet-driven flow. First, in the wider context, Mrk 78 is probably a post-merger system, with a nuclear dust lane, approximate r 1/4 continuum profile, and highly extended asymmetric gas distribution. The [O iii] and radio images both show complex structures with many similarities but also important differences. A careful comparison shows convincing morphological evidence for jet-gas interaction: (1) the western inner radio jet terminates and flares at the position of a bright [O iii] knot; (2) the weaker eastern radio jet changes direction as it encounters a large [O iii] knot; (3) most [O iii] features appear limb brightened on the upstream side, and flared on the downstream side; and (4) in the outer regions the radio components tend to lie between or adjacent to [O iii] knots, indicating the radio and line emitting phases do not easily interpenetrate. In addition to evidence of jet-gas interaction, two features indicate the importance of a central ionizing radiation field: an inner fanlike structure to the east, with a straight kinematically quiet northern edge; and an approximately fanlike extended narrow-line region to the west, lying well outside the radio source. The [O iii] line profiles from 10 Faint Object Spectrograph apertures provide further kinematic insight into the jet-gas interaction. (1) On the eastern side, where the radio source is deflected, the [O iii] profile contains a highly redshifted component ($700 km s À1) that is also narrow (FWHM 200 km s À1), indicating significant coherent gas acceleration with almost no induced turbulence. (2) At this location, the [O iii] profile is also double, suggesting lateral expansion away from a jet axis, as it burrows into the cloud complex. (3) In contrast, the bright western inner knot, which seems to disrupt the inner radio jet, has essentially undisturbed kinematics. (4) Across the outer complex western region, gas velocities are higher in the region center, decrease at the leading edge and may be highest where radio flows ''blow out'' of the region. Overall, morphology and kinematics suggest the western side is best described as an initially disrupted jet that then fills, accelerates, and leaks out of a complex incomplete ''bubble'' of ionized gas. The eastern side is best described as a large centrally illuminated fanlike gas structure that is penetrated, accelerated, and ultimately deflects the radio source. We use these different regions to construct a plausible evolutionary sequence: Initially, a dense (molecular?) cloud enters the jet flow and disrupts it (inner western knot); as time passes, the jet begins to penetrate, accelerate, and ablate the cloud (eastern knot complex); conti...

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Section: Discussionmentioning

confidence: 99%

Jet-Gas Interactions in Markarian 78. I. Morphology and Kinematics

Whittle¹,

Wilson²

2004

Astron J

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“…Jetcloud interactions are another possibility to drive local gas flows (e.g., Bicknell et al 2000, Saxton et al 2005, Wagner et al 2012, including the possibility of entrainment of NLR clouds in the radio plasma of the jets. Clouds are prone to instabilities under these conditions (e.g., Blandford & Königl 1979, Schiano et al 1995), but magnetic confinement has been suggested as a way out (Fedorenko et al 1996). Accretion disc winds, seen in some cases as ultrafast outflows in X-rays up to ∼0.1c (Tombesi et al 2012), may proceed into the inner NLR (Proga et al 2008) and beyond, and may then shock and accelerate the NLR clouds and drive a large-scale outflow (Wagner et al 2013, Cielo et al 2018.…”

Section: Models and Constraints From Observationsmentioning

confidence: 99%

Extreme gaseous outflows in radio-loud narrow-line Seyfert 1 galaxies

Komossa

Wagner

2018

Monthly Notices of the Royal Astronomical Society

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We present four radio-loud NLS1 galaxies with extreme emission-line shifts, indicating radial outflow velocities of the ionized gas of up to 2450 km/s, above the escape velocity of the host galaxies. The forbidden lines show strong broadening, up to 2270 km/s. An ionization stratification (higher line shift at higher ionization potential) implies that we see a large-scale outflow rather than single, localized jet-cloud interactions. Similarly, the paucity of zero-velocity [OIII]λ5007 emitting gas implies the absence of a second narrow-line region (NLR) component at rest, and therefore a large part of the high-ionization NLR is affected by the outflow. Given the radio loudness of these NLS1 galaxies, the observations are consistent with a pole on view onto their central engines, so that the effects of polar outflows are maximized. In addition, a very efficient driving mechanism is required, to reach the high observed velocities. We explore implications from recent hydrodynamic simulations of the interaction between fast winds or jets with the large-scale NLR. Overall, the best agreement with observations (and especially the high outflow speeds of the [NeV] emitting gas) can be reached if the NLS1 galaxies are relatively young sources with lifetimes not much exceeding 1 Myr. These systems represent sites of strong feedback at NLR scales at work, well below redshift one.

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“…Jet-cloud interaction can result in a variety of phenomena, including cloud entrainment, jet deflection and disruption and cloud destruction (e.g., Saxton et al 2005, Krause 2007 and references therein). Of interest here is entrainment (Blandford & Königl 1979, Schiano et al 1995, Fedorenko et al 1996. One key problem is cloud longevity against various instabilities.…”

Section: Cloud Acceleration By Radiation Pressure Acting On Dust -mentioning

confidence: 99%

On the Nature of Seyfert Galaxies with High [Oiii] λ5007 Blueshifts

Komossa

Zhou

et al. 2008

ApJ

188

291

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We have studied the properties of Seyfert galaxies with high [OIII]5007 blueshifts ("blue outliers"), originally identified because of their strong deviation from the M BH − σ relation of normal, narrowline Seyfert 1 (NLS1) and broad-line Seyfert 1 (BLS1) galaxies. These blue outliers turn out to be important test-beds for models of the narrow-line region (NLR), for mechanisms of driving large-scale outflows, for links between NLS1 galaxies and radio galaxies, and for orientation-dependent NLS1 models. We report the detection of a strong correlation of line blueshift with ionization potential in each galaxy, including the measurement of coronal lines with radial velocities up to 500-1000 km s −1 , and we confirm a strong correlation between [OIII] blueshift and line width. All [OIII] blue outliers have narrow widths of their broad Balmer lines and high Eddington ratios. While the presence of nonshifted low-ionization lines signifies the presence of a classical outer quiescent NLR in blue outliers, we also report the absence of any second, non-blueshifted [OIII] component from a classical inner NLR. These results place tight constraints on NLR models. We favor a scenario in which the NLR clouds are entrained in a decelerating wind which explains the strong stratification and the absence of a zero-blueshift inner NLR of blue outliers. The origin of the wind remains speculative at this time (collimated radio plasma, thermal winds, radiatively accelerated clouds). It is perhaps linked to the high Eddington ratios of blue outliers. Similar, less powerful winds could be present in all Seyfert galaxies, but would generally only affect the coronal line region (CLR), or level off even before reaching the CLR. Similarities between blue outliers in NLS1 galaxies and (compact) radio sources are briefly discussed.

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Interaction of Jets with Clouds in Extragalactic Radio Sources

Cited by 5 publications

References 3 publications

Jet-Gas Interactions in Markarian 78. I. Morphology and Kinematics

Jet-Gas Interactions in Markarian 78. I. Morphology and Kinematics

Extreme gaseous outflows in radio-loud narrow-line Seyfert 1 galaxies

On the Nature of Seyfert Galaxies with High [Oiii] λ5007 Blueshifts

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