Erratum: “<i>HST</i>and MERLIN Observations of 3C 264—A Laboratory for Jet Physics and Unified Schemes” (ApJ, 483, 178 [1997])

Baum, Stefi A.; O’Dea, C. P.; Giovannini, G.; Biretta, J. A.; Cotton, William B.; Koff, S. de; Feretti, L.; Golombek, Daniel; Lara, L.; Macchetto, F.; Miley, G. K.; Sparks, W. B.; Venturi, T.; Komissarov, S. S.

doi:10.1086/512828

Cited by 22 publications

(42 citation statements)

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“…This approach allowed us to use the variations of total intensity and linear polarization as independent constraints on the jet velocity field. We concluded that the magnetic structure and velocity field in 3C 31 are indeed significantly more complex than those assumed by Baum et al (1997). Nevertheless, we compared our models and the data for 3C 31 with their analytical solutions.…”

Section: Introductionmentioning

confidence: 84%

“…We now briefly recapitulate the analytical adiabatic relations derived by Baum et al (1997) for axisymmetric, decelerating, relativistic jets without velocity shear. Suppose that a jet has radius R, and that we can make the quasi-one-dimensional approximation: (a) that it is uniform in cross-section at a given distance from the nucleus and (b) that the velocity is unidirectional.…”

Section: Analytical Approximationsmentioning

confidence: 99%

“…LB showed that the analytical adiabatic approximation of Baum et al (1997) fails completely for the flaring region. We now examine whether this conclusion would be modified by including more realistic initial conditions and the effects of velocity shear by modelling the flaring and outer regions of 3C 31, setting the initial emissivity and field-ordering profiles at the boundary between the inner and flaring regions (r = r 1 ).…”

Section: Models With Initial Conditions Set At the Boundary Between Tmentioning

confidence: 99%

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Adiabatic relativistic models for the jets in the radio galaxy 3C 31

Laing

Bridle

2004

Monthly Notices of the Royal Astronomical Society

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We present a general approach to the modelling of the brightness and polarization structures of adiabatic, decelerating relativistic jets, based on the formalism of Matthews & Scheuer (1990). We compare the predictions of adiabatic jet models with deep, high-resolution observations of the radio jets in the FR I radio galaxy 3C 31. Adiabatic models require coupling between the variations of velocity, magnetic field and particle density. They are therefore more tightly constrained than the models previously presented for 3C 31 by Laing & Bridle (2002). We show that adiabatic models provide a poorer description of the data in two crucial respects: they cannot reproduce the observed magnetic-field structures in detail, and they also predict too steep a brightness decline along the jets for plausible variations of the jet velocity. We find that the innermost regions of the jets show the strongest evidence for non-adiabatic behaviour, and that the adiabatic models provide progressively better descriptions of the jet emission at larger distances from the galactic nucleus. We briefly discuss physical processes which might contribute to this non-adiabatic behaviour. In particular, we develop a parameterized description of distributed particle injection, which we fit to the observed total intensities. We show that particles are preferentially injected where bright X-ray emission is observed, and where we infer that the jets are over-pressured.Comment: 16 pages, 11 figures, accepted for publication in MNRA

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Section: Introductionmentioning

confidence: 84%

Section: Analytical Approximationsmentioning

confidence: 99%

Section: Models With Initial Conditions Set At the Boundary Between Tmentioning

confidence: 99%

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Adiabatic relativistic models for the jets in the radio galaxy 3C 31

Laing

Bridle

2004

Monthly Notices of the Royal Astronomical Society

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“…where x is the jet radius (Baum et al 1997). Figs 19 -21 show comparisons of the predictions of equations (31) -(32) with our model component ratios for on-axis and edge streamlines.…”

Section: Evolution Of the Magnetic Fieldmentioning

confidence: 98%

Systematic properties of decelerating relativistic jets in low-luminosity radio galaxies

Laing

Bridle

2013

Monthly Notices of the Royal Astronomical Society

156

176

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We model the kiloparsec-scale synchrotron emission from jets in 10 Fanaroff-Riley Class I radio galaxies for which we have sensitive, high-resolution imaging and polarimetry from the Very Large Array. We assume that the jets are intrinsically symmetrical, axisymmetric, decelerating, relativistic outflows and we infer their inclination angles and the spatial variations of their flow velocities, magnetic field structures and emissivities using a common set of fitting functions. The inferred inclinations agree well with independent indicators. The spreading rates increase rapidly, then decrease, in a flaring region. The jets then recollimate to form conical outer regions at distance r 0 from the active galactic nucleus (AGN). The flaring regions are homologous when scaled by r 0 . At ≈0.1r 0 , the jets brighten abruptly at the onset of a high-emissivity region and we find an outflow speed of ≈0.8c, with a uniform transverse profile. Jet deceleration first becomes detectable at ≈0.2r 0 and the outflow often becomes slower at its edges than it is on-axis. Deceleration continues until ≈0.6r 0 , after which the outflow speed is usually constant. The dominant magnetic-field component is longitudinal close to the AGN and toroidal after recollimation, but the field evolution is initially much slower than predicted by flux-freezing. In the flaring region, acceleration of ultrarelativistic particles is required to counterbalance the effects of adiabatic losses and account for observed X-ray synchrotron emission, but the brightness evolution of the outer jets is consistent with adiabatic losses alone. We interpret our results as effects of the interaction between the jets and their surroundings. The initial increase in brightness occurs in a rapidly falling external pressure gradient in a hot, dense, kpcscale corona around the AGN. We interpret the high-emissivity region as the base of a transonic 'spine' and suggest that a subsonic shear layer starts to penetrate the flow there. Most of the resulting entrainment must occur before the jets start to recollimate.

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“…NGC 3862 is signi®cantly offset from the centre of the highly extended X-ray emission, and is observed to have a weak emission line spectrum ([N ii]>Ha, weak [O ii]) with evidence for a blue continuum. HST observations reveal that 3C264 contains a non-thermal core and jet (Baum et al 1998), which could contribute to this blue continuum. We have observed the galaxy NGC 3860 at RA 11 h 44 m 49 s .1, Dec. 198 47 H 44 HH (J2000), which is the brightest galaxy in the broad cluster core.…”

Section: Occurrence Of Line Emissionmentioning

confidence: 99%

The ROSAT Brightest Cluster Sample -- III. Optical spectra of the central cluster galaxies

Crawford

Allen

Ebeling

et al. 1999

Monthly Notices of the Royal Astronomical Society

402

663

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We present new spectra of dominant galaxies in X‐ray‐selected clusters of galaxies, which combine with our previously published spectra to form a sample of 256 dominant galaxies in 215 clusters. 177 of the clusters are members of the ROSAT Brightest Cluster Sample (BCS; Ebeling et al.), and 17 have no previous measured redshift. This is the first paper in a series correlating the properties of brightest cluster galaxies and their host clusters in the radio, optical and X‐ray wavebands. 27 per cent of the central dominant galaxies have emission‐line spectra, all but five with line intensity ratios typical of cooling flow nebulae. A further 6 per cent show only [N ii]λλ6548,6584 with Hα in absorption. We find no evidence for an increase in the frequency of line emission with X‐ray luminosity. Purely X‐ray‐selected clusters at low redshift have a higher probability of containing line emission. The projected separation between the optical position of the dominant galaxy and its host cluster X‐ray centroid is less for the line‐emitting galaxies than for those without line emission, consistent with a closer association of the central galaxy and the gravitational centre in cooling flow clusters. The more Hα‐luminous galaxies have larger emission‐line regions and show a higher ratio of Balmer to forbidden line emission, although there is a continuous trend of ionization behaviour across four decades in Hα luminosity. Galaxies with the more luminous line emission [L(Hα)> 1041ergs−1] show a significantly bluer continuum, whereas lower luminosity and [N ii]‐only line emitters have continua that differ little from those of non‐line‐emitting dominant galaxies. Values of the Balmer decrement in the more luminous systems commonly imply intrinsic reddening of E(B−V)∼0.3 and, when this is corrected for, the excess blue light can be characterized by a population of massive young stars. Several of the galaxies require a large population of O stars, which also provide sufficient photoionization to produce the observed Hα luminosity. The large number of lower mass stars relative to the O‐star population suggests that this anomalous population is caused by a series of starbursts in the central galaxy. The lower Hα‐luminosity systems show a higher ionization state and few massive stars, requiring instead the introduction of a harder source of photoionization, such as turbulent mixing layers, or low‐level nuclear activity. The line emission from the systems showing only [N ii] is very similar to low‐level LINER activity commonly found in many normal elliptical galaxies.

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Erratum: “HSTand MERLIN Observations of 3C 264—A Laboratory for Jet Physics and Unified Schemes” (ApJ, 483, 178 [1997])

Cited by 22 publications

References 0 publications

Adiabatic relativistic models for the jets in the radio galaxy 3C 31

Adiabatic relativistic models for the jets in the radio galaxy 3C 31

Systematic properties of decelerating relativistic jets in low-luminosity radio galaxies

The ROSAT Brightest Cluster Sample -- III. Optical spectra of the central cluster galaxies

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