The nature of the optical-radio correlations for powerful radio galaxies

Tadhunter, C. N.; Morganti, Raffaella; Robinson, Andrew; Dickson, Robert C.; Villar-Martı́n, M.; Fosbury, R. A. E.

doi:10.1046/j.1365-8711.1998.01706.x

Cited by 134 publications

(250 citation statements)

References 40 publications

(69 reference statements)

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“…In NVSS J004000−303333 we find two very faint unresolved continuum emitters of about equal flux, perhaps indicating an ongoing interaction of two galaxies, or AGN light scattered on extended dust (e.g., Hatch et al 2009). Both blobs are roughly along the radio jet axis, somewhat reminiscent of the alignment effect found in more powerful HzRGs (Tadhunter et al 1998;Vernet et al 2001). In NVSS J234235−384526 we do not detect the continuum at all.…”

Section: Rest-frame Optical Continuummentioning

confidence: 55%

“…Whereas the jets of powerful radio galaxies in the local Universe are known to affect the gas locally within extended gas disks ("jet-cloud interactions", e.g., Tadhunter et al 1998;van Breugel et al 1985), it was found only recently that outflows driven by the most powerful radio jets in the early universe at z ∼ 2 can encompass very high gas masses, up to about 10 10 M in the most powerful radio galaxies at high redshift (Nesvadba et al 2006(Nesvadba et al , 2008a. This is similar to the typical total gas masses in massive, intensely star-forming, high-redshift galaxies of a few 10 10 M (e.g., Greve et al 2005;Tacconi et al 2008).…”

Section: Introductionmentioning

confidence: 99%

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Kinematic signatures of AGN feedback in moderately powerful radio galaxies atz~ 2 observed with SINFONI

Collet

Nesvadba

Breuck

et al. 2016

A&A

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Most successful galaxy formation scenarios now postulate that the intense star formation in massive, high-redshift galaxies during their major growth period was truncated when powerful AGNs launched galaxy-wide outflows of gas that removed large parts of the interstellar medium. SINFONI imaging spectroscopy of the most powerful radio galaxies at z ∼ 2 show clear signatures of such winds, but are too rare to be good representatives of a generic phase in the evolution of all massive galaxies at high redshift. Here we present SINFONI imaging spectroscopy of the rest-frame optical emission-line gas in 12 radio galaxies at redshifts ∼2. Our sample spans a range in radio power that is intermediate between the most powerful radio galaxies with known wind signatures at these redshifts and vigorous starburst galaxies, and are about two orders of magnitude more common than the most powerful radio galaxies. Thus, if AGN feedback is a generic phase of massive galaxy evolution for reasonable values of the AGN duty cycle, these are just the sources where AGN feedback should be most important. Our sources show a diverse set of gas kinematics ranging from regular velocity gradients with amplitudes of Δv = 200−400 km s −1 consistent with rotating disks to very irregular kinematics with multiple velocity jumps of a few 100 km s −1 . Line widths are generally high, typically around FWHM = 800 km s −1 , more similar to the more powerful high-z radio galaxies than mass-selected samples of massive high-z galaxies without bright AGNs, and consistent with the velocity range expected from recent hydrodynamic models. A broad Hα line in one target implies a black hole mass of a few 10 9 M . Velocity offsets of putative satellite galaxies near a few targets suggest dynamical masses of a few 10 11 M for our sources, akin to the most powerful high-z radio galaxies. Ionized gas masses are 1−2 orders of magnitude lower than in the most powerful radio galaxies, and the extinction in the gas is relatively low, up to A V ∼ 2 mag. The ratio of line widths, σ, to bulk velocity, v, is so large that even the gas in galaxies with regular velocity fields is unlikely to be gravitationally bound. It is unclear, however, whether the large line widths are due to turbulence or unresolved, local outflows as are sometimes observed at low redshifts. We compare our sources with sets of radio galaxies at low and high redshift, finding that they may have more in common with gas-rich nearby radio galaxies with similar jet power than with the most powerful high-z radio galaxies. Comparison of the kinetic energy with the energy supply from the AGNs through jet and radiation pressure suggests that the radio source still plays a dominant role for feedback, consistent with low-redshift radio-loud quasars.

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Section: Rest-frame Optical Continuummentioning

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Kinematic signatures of AGN feedback in moderately powerful radio galaxies atz~ 2 observed with SINFONI

Collet

Nesvadba

Breuck

et al. 2016

A&A

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“…5). In this sense it is similar to the WLRG, that are defined to have small [OIII]λ5007 emission line equivalent widths (EW [OIII] < 10 Å, see Tadhunter et al 1998). However, in contrast to the other WLRG in the 2 Jy sample, our previous spectroscopic investigation of PKS 1814-637 (see Holt et al 2008) suggested a higher equivalent width and classification as a NLRG.…”

Section: Optical Spectral Classificationmentioning

confidence: 86%

PKS 1814-637: a powerful radio-loud AGN in a disk galaxy

Morganti

Holt

Tadhunter

et al. 2011

A&A

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We present a detailed study of PKS 1814-637, a rare case of powerful radio source (P 5 GHz = 4.1 × 10 25 W Hz −1 ) hosted by a disk galaxy. Optical images have been used to model the host galaxy morphology confirming it to be dominated by a strong (and warped) disk component that is observed close to edge-on to the line of sight. This is the first radio galaxy found to reside in a disk dominated galaxy with radio luminosity equivalent to powerful FRII objects. At radio wavelengths, PKS 1814-637 is about 480 pc in diameter and it is classified as a compact steep spectrum (CSS) source; such sources are usually considered to be radio sources observed in the early stages of their evolution. However, the optical and mid-IR spectroscopic properties of PKS1814-637 show more in common with Seyfert galaxies than they do with radio galaxies, with the detection of H 2 , and PAH emission features, along with HI and silicate absorption features, providing evidence for a rich ISM which is likely to be related to the disk morphology of the host galaxy. We argue that the interaction between the radio plasma and the rich ISM in this and similar objects may have boosted their radio emission, allowing them to more easily enter flux limited samples of radio sources. In this case, PKS 1814-637 represents a type of "imposter": an intrinsically low power object that is selected in a radio flux limited sample because of the unusually efficient conversion of jet power into radio emission. This would make PKS 1814-637 an extreme example of the effects of jet-cloud interactions in galaxies containing a rich ISM, and perhaps a missing link between radio galaxies and radio-loud Seyfert galaxies. However, it is unlikely that jet-cloud interactions alone can account for the unusually powerful radio emission compared to Seyfert galaxies, and it is probable that the jet in PKS 1814-637 is also intrinsically more powerful than in typical Seyfert galaxies, perhaps due to a higher bulge and black hole mass. The estimated BH mass is indeed higher than the majority of Seyfert galaxies in the local Universe. We speculate that sources similar to PKS1814-637 are likely to be more common at high redshifts, because of the enhanced probability at earlier epochs of triggering radio sources in moderately massive bulges that are also gas-rich.

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“…This work was originally motivated in part by the desire to find the first powerful radio galaxies, at very high redshifts (z>5; van Breugel et al 1999). While LDRRGs have been proposed as candidates for very high redshift radio galaxies (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…They are hosted by massive elliptical galaxies or their progenitors, and can be detected across a vast range in redshift (z∼0 to z>5: e.g. van Breugel et al 1999). In observing a powerful radio galaxy we get to see a massive galaxy as it undergoes a phase of significant accretion of matter onto its supermassive black hole, the radiative and mechanical output from which can potentially affect the subsequent stellar mass assembly activity and the gaseous properties of the galaxy.…”

Section: Introductionmentioning

confidence: 99%

Witnessing the transformation of a quasar host galaxy at z = 1.6

Humphrey

Roche

Gomes

et al. 2015

Monthly Notices of the Royal Astronomical Society

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A significant minority of high redshift radio galaxy (HzRG) candidates show extremely red broad band colours and remain undetected in emission lines after optical 'discovery' spectroscopy. In this paper we present deep GTC optical imaging and spectroscopy of one such radio galaxy, 5C 7.245, with the aim of better understanding the nature of these enigmatic objects. Our g-band image shows no significant emission coincident with the stellar emission of the host galaxy, but does reveal faint emission offset by ∼3 ′′ (26 kpc) therefrom along a similar position angle to that of the radio jets, reminiscent of the 'alignment effect' often seen in the optically luminous HzRGs. This offset g-band source is also detected in several UV emission lines, giving it a redshift of 1.609, with emission line flux ratios inconsistent with photoionization by young stars or an AGN, but consistent with ionization by fast shocks. Based on its unusual gas geometry, we argue that in 5C 7.245 we are witnessing a rare (or rarely observed) phase in the evolution of quasar hosts when stellar mass assembly, accretion onto the back hole, and powerful feedback activity has eradicated its cold gas from the central ∼20 kpc, but is still in the process of cleansing cold gas from its extended halo.

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The nature of the optical-radio correlations for powerful radio galaxies

Cited by 134 publications

References 40 publications

Kinematic signatures of AGN feedback in moderately powerful radio galaxies atz~ 2 observed with SINFONI

Kinematic signatures of AGN feedback in moderately powerful radio galaxies atz~ 2 observed with SINFONI

PKS 1814-637: a powerful radio-loud AGN in a disk galaxy

Witnessing the transformation of a quasar host galaxy at z = 1.6

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