Multiwavelength Evidence of the Physical Processes in Radio Jets

Worrall, D. M.; Birkinshaw, Mark

doi:10.1007/3-540-34621-x_2

Cited by 46 publications

(31 citation statements)

References 137 publications

(231 reference statements)

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“…In Section 4.2.4, we model the spectral energy distribution (SED) by incorporating a low-energy cutoff in the electron energy distribution. A low-energy cutoff at some minimum Lorentz factor γ min produces a spectrum with F ν ∝ ν 1/3 at frequencies below the characteristic emission frequency of electrons with a Lorentz factor γ min (see e.g., Worrall & Birkinshaw 2006). We must emphasize that an instantaneous cutoff in number density is not physical-it is merely an approximation to a sharp turnover in the electron energy distribution.…”

Section: Modeling the Hotspot Spectral Energy Distribution 421 Lowmentioning

confidence: 99%

“…f (e.g., Worrall & Birkinshaw 2006). Equation (15) exhibits a strong dependence on the Doppler factor because of the strong dependence of the break frequency on the magnetic field strength.…”

Section: Synchrotron Cooling Breakmentioning

confidence: 99%

“…The standard expressions for the synchrotron spectrum produced by an arbitrary electron energy distribution contain a dependence on the angle between the line of sight and the magnetic field (see e.g., Worrall & Birkinshaw 2006). If the magnetic field direction changes significantly throughout the volume in which the observed flux is produced, it is appropriate to use the angle-averaged emission spectrum to model the source.…”

Section: A1 Angle-averaged Synchrotron Flux Density For An Arbitrarmentioning

confidence: 99%

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A Multiwavelength Study of the High Surface Brightness Hot Spot in PKS 1421–490

Godfrey

Bicknell

Lovell

et al. 2009

ApJ

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Long Baseline Array imaging of the z = 0.663 broadline radio galaxy PKS 1421−490 reveals a 400 pc diameter high surface brightness hot spot at a projected distance of ∼40 kpc from the active galactic nucleus. The isotropic X-ray luminosity of the hot spot, L 2-10 keV = 3 × 10 44 ergs s −1 , is comparable to the isotropic X-ray luminosity of the entire X-ray jet of PKS 0637−752, and the peak radio surface brightness is hundreds of times greater than that of the brightest hot spot in Cygnus A. We model the radio to X-ray spectral energy distribution using a one-zone synchrotron self-Compton model with a near equipartition magnetic field strength of 3 mG. There is a strong brightness asymmetry between the approaching and receding hotspots and the hot spot spectrum remains flat (α ≈ 0.5) well beyond the predicted cooling break for a 3 mG magnetic field, indicating that the hotspot emission may be Doppler beamed. A high plasma velocity beyond the terminal jet shock could be the result of a dynamically important magnetic field in the jet. There is a change in the slope of the hotspot radio spectrum at GHz frequencies, which we model by incorporating a cutoff in the electron energy distribution at γ min ≈ 650, with higher values implied if the hotspot emission is Doppler beamed. We show that a sharp decrease in the electron number density below a Lorentz factor of 650 would arise from the dissipation of bulk kinetic energy in an electron/proton jet with a Lorentz factor Γ jet 5.

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Section: Modeling the Hotspot Spectral Energy Distribution 421 Lowmentioning

confidence: 99%

Section: Synchrotron Cooling Breakmentioning

confidence: 99%

Section: A1 Angle-averaged Synchrotron Flux Density For An Arbitrarmentioning

confidence: 99%

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A Multiwavelength Study of the High Surface Brightness Hot Spot in PKS 1421–490

Godfrey

Bicknell

Lovell

et al. 2009

ApJ

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“…3) and average spectral properties (Fig. 4) using equations given in Birkinshaw & Worrall (1993) and Worrall & Birkinshaw (2006). We conclude that PKS B1416−493 lies in an extreme atmosphere amongst the studied FR I/II boundary objects.…”

Section: Large-scale X-ray Emissionmentioning

confidence: 77%

A non cool-core 4.6-keV cluster around the bright nearby radio galaxy PKS B1416−493

Worrall¹,

Birkinshaw²

2017

Monthly Notices of the Royal Astronomical Society

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We present new X-ray (Chandra) and radio (ATCA) observations of the z = 0.09 radio galaxy PKS B1416−493, a member of the southern equivalent of the 3CRR sample. We find the source to be embedded in a previously unrecognized bright kT = 4.6-keV non cool-core cluster. The discovery of new clusters of such high temperature and luminosity within z = 0.1 is rare. The radio source was chosen for observation based on its intermediate FR I/II morphology. We identify a cavity coincident with the northeast lobe, and excess counts associated with the southwest lobe that we interpret as inverse Compton X-ray emission. The jet power, at 5.3 × 10 44 erg s −1 , when weighted by radio source density, supports suggestions that radio sources of intermediate morphology and radio power may dominate radio-galaxy heating in the local Universe.

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“…The radio flux should also be high in this scenario. However, the X-ray spectra of Galactic and extragalactic jet sources are typically much steeper than that of source 6, and the observed inverted radio spectrum is not typical of jets that have radio spectral indices near À0.6 (Worrall & Birkinshaw 2005). On the other hand, an inverted spectrum and a lack of polarization are indicative of compact cores of radio galaxies.…”

Section: Ulx Candidatementioning

confidence: 93%

A Multiwavelength Study of the X‐Ray Sources in NGC 5018

Ghosh

Swartz

Tennant

et al. 2005

ApJ

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The E3 giant elliptical galaxy NGC 5018 was observed with the Chandra X-Ray Observatory's Advanced CCD Imaging Spectrometer for 30 ks on 2001 April 14. Results of the analysis of these X-ray data as well as of complementary optical, infrared, and radio data are reported. Seven X-ray point sources, including the nucleus, were detected. If they are intrinsic to NGC 5018, then all six nonnuclear sources have luminosities exceeding 10 39 ergs s À1 in the 0.5-8.0 keVenergy band, placing them in the class of ultraluminous X-ray sources. Comparison of X-ray source positions to archival Hubble Space Telescope Wide Field Planetary Camera 2 (HST WFPC2) images reveals that four of the six nonnuclear sources are spatially coincident with bright, M V P À8:6 mag objects. These four objects have optical magnitudes and (V À I ) colors consistent with globular clusters in NGC 5018, but they also have X-ray-to-optical flux ratios consistent with background active galactic nuclei (AGNs). Strong, unpolarized radio emission has been detected from one of the optically bright counterparts. Another optically bright counterpart was observed to vary by $1 mag in optical observations taken on 1997 July 28 and 1999 February 4. Extended X-ray emission is detected within an $15 00 radius of the galaxy center at a luminosity of $10 40 ergs s À1 in the X-ray band. Its thermal X-ray spectrum (kT $ 0:4 keV) and its spatial coincidence with strong H emission are consistent with a hot gas origin. The nucleus itself may be a weak X-ray source, L X P 3:5 ; 10 39 ergs s À1 , which displays a radio spectrum typical of AGNs.

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Multiwavelength Evidence of the Physical Processes in Radio Jets

Cited by 46 publications

References 137 publications

A Multiwavelength Study of the High Surface Brightness Hot Spot in PKS 1421–490

A Multiwavelength Study of the High Surface Brightness Hot Spot in PKS 1421–490

A non cool-core 4.6-keV cluster around the bright nearby radio galaxy PKS B1416−493

A Multiwavelength Study of the X‐Ray Sources in NGC 5018

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