The morphological classification of distant radio galaxies explored with three-dimensional simulations

Smith, Michael D.; Donohoe, Justin

doi:10.1093/mnras/stz2525

Cited by 18 publications

(11 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The size and time coverage of our data set provides a unique opportunity to examine the stability of the innermost regions of AGN jets over time. Although smoking gun evidence of AGN jet precession has been seen on kpc-scales (e.g., Smith & Donohoe 2019;Falceta-Gonçalves et al 2010;Gower et al 1982), there have been few large systematic pc-scale studies to date. In Lister et al (2013) we identified several individual cases of AGN that may be undergoing periodic changes in their inner jet position angle (PA).…”

Section: Introductionmentioning

confidence: 99%

MOJAVE: XVIII. Kinematics and Inner Jet Evolution of Bright Radio-Loud Active Galaxies

Lister,

Homan,

Kellermann

et al. 2021

Preprint

View full text Add to dashboard Cite

We have analyzed the parsec-scale jet kinematics of 447 bright radio-loud AGN, based on 15 GHz VLBA data obtained between 1994 August 31 and 2019 August 4. We present new total intensity and linear polarization maps obtained between 2017 January 1 to 2019 August 4 for 143 of these AGN. We tracked 1923 bright features for five or more epochs in 419 jets. A majority (60%) of the well-sampled jet features show either accelerated or non-radial motion. In 47 jets there is at least one non-accelerating feature with an unusually slow apparent speed. Most of the jets show variations of 10 • to 50 • in their inner jet position angle (PA) over time, although the overall distribution has a continuous tail out to 200 • . AGN with SEDs peaked at lower frequencies tend to have more variable PAs, with BL Lacs being less variable than quasars. The Fermi LAT gamma-ray associated AGN also tend to have more variable PAs than the non-LAT AGN in our sample. We attribute these trends to smaller viewing angles for the lower spectral peaked and LAT-associated jets. We identified 13 AGN where multiple features emerge over decade-long periods at systematically increasing or decreasing PAs. Since the ejected features do not fill the entire jet cross-section, this behavior is indicative of a precessing flow instability near the jet base. Although some jets show indications of oscillatory PA evolution, we claim no bona fide cases of periodicity since the fitted periods are comparable to the total VLBA time coverage.

show abstract

Section: Introductionmentioning

confidence: 99%

MOJAVE: XVIII. Kinematics and Inner Jet Evolution of Bright Radio-Loud Active Galaxies

Lister,

Homan,

Kellermann

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…In real-world radio sources, hydrodynamic processes in lobes can push jets away from their ballistic paths, and may also disrupt them. Still, hydrodynamic models have also shown the development of characteristic precession signatures (e.g., Cox et al 1991;Donohoe & Smith 2016;Smith & Donohoe 2019), whilst such signatures are absent in simulations of non-precessing jets (e.g., English, Hardcastle & Krause 2016).…”

Section: Introductionmentioning

confidence: 99%

3D hydrodynamic simulations of large-scale precessing jets: radio morphology

Horton

Krause

Hardcastle

2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

The prospect of relativistic jets exhibiting complex morphologies as a consequence of geodetic precession has long been hypothesised. We have carried out a 3D hydrodynamics simulation study varying the precession cone angle, jet injection speed and number of turns per simulation time. Using proxies for the radio emission we project the sources with different inclinations to the line of sight to the observer. We find that a number of different precession combinations result in characteristic ‘X’ shaped sources which are frequently observed in radio data, and some precessing jet morphologies may mimic the morphological signatures of restarting radio sources. We look at jets ranging in scale from tens to hundreds of kiloparsecs and develop tools for identifying known precession indicators of point symmetry, curvature and jet misalignment from the lobe axis and show that, based on our simulation sample of precessing and non-precessing jets, a radio source that displays any of these indicators has a 98% chance of being a precessing source.

show abstract

“…The simulations analysed here have been introduced in Paper 1 (Donohoe & Smith 2016) for their physical attributes and in Paper 2 (Smith & Donohoe 2019). for their radio morphology and classification.…”

Section: Simulation and Display Parametersmentioning

confidence: 99%

“…We aim to account for the Mach number, pre-E-mail: m.d.smith@kent.ac.uk † E-mail: jd440@kent.ac.uk, cession and orientation in order to provide a rich bank of simulated images. The physical properties and radio morphologies have already been published for this set of three-dimensional simulations in Paper 1 (Donohoe & Smith 2016) and Paper 2 (Smith & Donohoe 2019). We thereby wish to probe the implications for the intracluster medium.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional simulations of X-ray cavities inflated by radio galaxies

Smith

Donohoe

2021

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

Vast cavities in the intergalactic medium are excavated by radio galaxies. The cavities appear as such in X-ray images because the external medium has been swept-up, leaving a hot but low-density bubble surrounding the radio lobes. We explore here the predicted thermal X-ray emission from a large set of high-resolution three-dimensional simulations of radio galaxies driven by supersonic jets. We assume adiabatic non-relativistic hydrodynamics with injected straight and precessing jets of supersonic gas emitted from nozzles. Images of X-ray bremsstrahlung emission tend to generate oval cavities in the soft keV bands and leading arcuate structures in hard X-rays. However, the cavity shape is sensitive to the jet-ambient density contrast, varying from concave-shaped at η = 0.1 to convex for η = 0.0001 where η is the jet/ambient density ratio. We find lateral ribs in the soft X-rays in certain cases and propose this as an explanation for those detected in the vicinity of Cygnus A. In bi-lobed or X-shaped sources and in curved or deflected jets, the strongest X-ray emission is not associated with the hotspot but with the relic lobe or deflection location. This is because the hot high-pressure and dense high-compression regions do not coincide. Directed towards the observer, the cavity becomes a deep round hole surrounded by circular ripples. With short radio-mode outbursts with a duty cycle of 10 per cent, the intracluster medium simmers with low Mach number shocks widely dissipating the jet energy in between active jet episodes.

show abstract

The morphological classification of distant radio galaxies explored with three-dimensional simulations

Cited by 18 publications

References 71 publications

MOJAVE: XVIII. Kinematics and Inner Jet Evolution of Bright Radio-Loud Active Galaxies

MOJAVE: XVIII. Kinematics and Inner Jet Evolution of Bright Radio-Loud Active Galaxies

3D hydrodynamic simulations of large-scale precessing jets: radio morphology

Three-dimensional simulations of X-ray cavities inflated by radio galaxies

Contact Info

Product

Resources

About