Magnetic field strengths in the hotspots of 3C 33 and 111

Hardcastle, M. J.; Birkinshaw, Mark; Worrall, D. M.

doi:10.1111/j.1365-8711.1998.01159.x

Cited by 78 publications

(82 citation statements)

References 28 publications

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“…Since the appearance of earlier work aimed explicitly at detecting hot spots (Harris et al 2000;Hardcastle et al 2001a;H02;Brunetti et al 2002), a number of hot spots have been detected in Chandra observations of FR II radio galaxies and quasars made for other purposes (e.g., Donahue et al 2003;. This has motivated us to collate all existing data on the hot spots of 3C radio sources from the Chandra archive and analyze them in a systematic way, with the aim of determining trends and testing models.…”

Section: Introductionmentioning

confidence: 99%

The Origins of X‐Ray Emission from the Hot Spots of FR II Radio Sources

Hardcastle

Harris

Worrall

et al. 2004

ApJ

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We use new and archival Chandra data to investigate the X-ray emission from a large sample of compact hot spots of FR II radio galaxies and quasars from the 3C catalog. We find that only the most luminous hot spots tend to be in good agreement with the predictions of a synchrotron self-Compton model with equipartition magnetic fields. At low hot spot luminosities inverse Compton predictions are routinely exceeded by several orders of magnitude, but this is never seen in more luminous hot spots. We argue that an additional synchrotron component of the X-ray emission is present in low-luminosity hot spots and that the hot spot luminosity controls the ability of a given hot spot to produce synchrotron X-rays, probably by determining the high-energy cutoff of the electron energy spectrum. It remains plausible that all hot spots are close to the equipartition condition.

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Section: Introductionmentioning

confidence: 99%

The Origins of X‐Ray Emission from the Hot Spots of FR II Radio Sources

Hardcastle

Harris

Worrall

et al. 2004

ApJ

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174

224

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“…We have previously shown that X-ray inverse-Compton limits rule out such models in several individual cases (Hardcastle et al 1998;Croston et al 2003;Hardcastle & Croston 2010;Croston & Hardcastle 2014). For a subset of our FRI sample where the predicted levels are in principle detectable, we obtained upper limits on the lobe X-ray inverse-Compton emission, using the same method and assumptions as for the FRII inverseCompton measurements of I17.…”

Section: Samplementioning

confidence: 99%

“…We note that scenario (2) is already ruled out in some objects by X-ray inverse Compton limits (see Section 2.3); however, we wanted in this study to consider the population as a whole. For both scenarios the internal pressures are calculated using the SYNCH code of Hardcastle et al (1998), with the same electron energy distribution assumptions as for the FRII results of I17. The lobes are modelled as having uniform internal pressure.…”

Section: A Comparison Of Fri and Frii Pressure Ratiosmentioning

confidence: 99%

Particle content, radio-galaxy morphology, and jet power: all radio-loud AGN are not equal

Croston

Ineson

Hardcastle

2018

Monthly Notices of the Royal Astronomical Society

122

123

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Ongoing and future radio surveys aim to trace the evolution of black hole growth and feedback from active galactic nuclei (AGN) throughout cosmic time; however, there remain major uncertainties in translating radio luminosity functions into a reliable assessment of the energy input as a function of galaxy and/or dark matter halo mass. A crucial and long-standing problem is the composition of the radio-lobe plasma that traces AGN jet activity. In this paper, we carry out a systematic comparison of the plasma conditions in Fanaroff & Riley class I and II radio galaxies to demonstrate conclusively that their internal composition is systematically different. This difference is best explained by the presence of an energetically dominant proton population in the FRI, but not the FRII radio galaxies. We show that, as expected from this systematic difference in particle content, radio morphology also affects the jet-power/radioluminosity relationship, with FRII radio galaxies having a significantly lower ratio of jet power to radio luminosity than the FRI cluster radio sources used to derive jet-power scaling relations via X-ray cavity measurements. Finally we also demonstrate conclusively that lobe composition is unconnected to accretion mode (optical excitation class): the internal conditions of low-and high-excitation FRII radio lobes are indistinguishable. We conclude that inferences of population-wide AGN impact require careful assessment of the contribution of different jet sub-classes, particularly given the increased diversity of jet evolutionary states expected to be present in deep, low-frequency radio surveys such as the LOFAR Two-Metre Sky Survey.

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“…Previous nuclear observations of 3C 33 in the X-ray band date to those of the EINSTEIN observatory (Fabbiano et al 1984) and ROSAT (Hardcastle et al 1998;Hardcastle & Worrall 1999) X-ray telescopes. EINSTEIN only provided an upper limit to the 0.5−3 keV luminosity, while ROSAT/HRI could detect the source in the soft X-ray band, although the HRI instrument onboard was not able to resolve the source.…”

Section: Introductionmentioning

confidence: 99%

3C 33: another case of photoionized soft X-ray emission in radio galaxies

Torresi

Grandi

Guainazzi

et al. 2009

A&A

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We investigate the X-ray spectral properties of 3C 33 by analyzing all the observations available in the Chandra and XMM-Newton archives. In this paper we present a complete X-ray analysis of the nuclear emission of this narrow-line radio galaxy. The broad-band spectrum of 3C 33 is complex. Its hard part resembles that of Seyfert 2 galaxies, which have a heavily obscured nuclear continuum (N H ∼ 10 23 cm −2 ) and a prominent Fe Kα line. This represents the nuclear radiation observed directly in transmission through a cold circumnuclear gas. On the other hand an unabsorbed continuum plus emission lines seem to reproduce the soft part of the spectrum (0.5−2 keV) well, suggesting that the jet does not contribute significantly to the X-ray emission. We discuss the possible collisional or photoionized origin of the gas that emits the soft X-ray lines. Our results, supported by those from optical spectroscopy, favor the photoionization scenario.

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Magnetic field strengths in the hotspots of 3C 33 and 111

Cited by 78 publications

References 28 publications

The Origins of X‐Ray Emission from the Hot Spots of FR II Radio Sources

The Origins of X‐Ray Emission from the Hot Spots of FR II Radio Sources

Particle content, radio-galaxy morphology, and jet power: all radio-loud AGN are not equal

3C 33: another case of photoionized soft X-ray emission in radio galaxies

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