The X-ray jet and halo of PKS 0521−365

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

doi:10.1046/j.1365-8711.2002.05615.x

Cited by 46 publications

(64 citation statements)

References 30 publications

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“…SYN sources are mainly found as jet knots in nearby low-luminosity radio galaxies, in agreement with previous studies (e.g., Pesce et al 2001;Birkinshaw et al 2002). If the magnetic field strength is not far from the equipartition value in these objects, the electrons must be accelerated very efficiently up to 10-100 TeV, in accordance with the general expectation that radio galaxies may be some of the most efficient particle accelerators in the universe (see a discussion in Kataoka et al 2003a).…”

Section: Discussionsupporting

confidence: 89%

X‐Ray Emission Properties of Large‐Scale Jets, Hot Spots, and Lobes in Active Galactic Nuclei

Kataoka

Stawarz

2005

ApJ

237

269

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We examine a systematic comparison of jet knots, hot spots, and radio lobes recently observed with Chandra and ASCA. This report discusses the origin of their X-ray emissions and investigates the dynamics of the jets. The data were compiled at well-sampled radio (5 GHz) and X-ray (1 keV ) frequencies for more than 40 radio galaxies. We examine three models for the X-ray production: synchrotron (SYN), synchrotron self-Compton (SSC), and external Compton ( EC) on cosmic microwave background (CMB) photons. For the SYN sources-mostly jet knots in nearby low-luminosity radio galaxies-X-ray photons are produced by ultrarelativistic electrons with energies 10-100 TeV that must be accelerated in situ. For the other objects, conservatively classified as SSC or EC sources, a simple formulation of calculating the ''expected'' X-ray fluxes under an equipartition hypothesis is presented. We confirm that the observed X-ray fluxes are close to the expected ones for nonrelativistic emitting plasma velocities in the case of radio lobes and the majority of hot spots, whereas a considerable fraction of jet knots are too bright in X-rays to be explained in this way. We examine two possibilities to account for the discrepancy in a framework of the inverse Compton model: (1) the magnetic field is much smaller than the equipartition value, and (2) the jets are highly relativistic on kiloparsec and megaparsec scales. We conclude that if the inverse Compton model is the case, the X-ray-bright jet knots are most likely far from the minimum-power condition. We also briefly discuss the other possibility, namely, that the observed X-ray emission from all the jet knots is synchrotron in origin.

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Section: Discussionsupporting

confidence: 89%

X‐Ray Emission Properties of Large‐Scale Jets, Hot Spots, and Lobes in Active Galactic Nuclei

Kataoka

Stawarz

2005

ApJ

237

269

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“…The measured steepening in the spectral index ( ) corresponds to a change in the electron disDa ∼ 0.8 tribution index (see below) of 1.6. Similar changes have D p been found for other well-studied high-energy (optical and Xray) synchrotron-emitting regions in the jets of, for instance, M87 (Marshall et al 2002) and PKS 0521Ϫ365 (Birkinshaw, Worrall, & Hardcastle 2002).…”

Section: Physical Conditions In the Optical/uv-emitting Regionsupporting

confidence: 83%

Detection of Optical Synchrotron Emission from the Radio Jet of 3C 279

Cheung

2002

The Astrophysical Journal

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We report the detection of optical and ultraviolet emission from the kiloparsec-scale jet of the well-known quasar 3C 279. A bright knot, discovered in archival V-and U-band Hubble Space Telescope Faint Object Camera images, is coincident with a peak in the radio jet ∼0Љ .6 from the nucleus. The detection was also confirmed in Wide Field Planetary Camera 2 images. Archival Very Large Array and MERLIN radio data are also analyzed, and these data help to show that the high-energy optical/UV continuum and the spectrum are consistent with a synchrotron origin from the same population of relativistic electrons responsible for the radio emission.

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“…They are interpreted as a result of the Compton scattering cosmic microwave background photons off the most energetic electrons (Schwartz et al, 2000;Tavecchio et al, 2000;Celotti et al, 2001). Jet morphology in X-ray was studied in some details for a number of close-by BLLs, like PKS 0521-365 (Birkinshaw et al, 2002), and PKS 2201+044 and 3C 371 (Sambruna et al, 2007), which notably are systems where the beaming is supposed to be modest. Knot structures are observed.…”

Section: Jetsmentioning

confidence: 99%

An optical view of BL Lacertae objects

Falomo

Pian²,

Treves

2014

Astron Astrophys Rev

140

109

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BL Lac objects are active nuclei, hosted in massive elliptical galaxies, the emission of which is dominated by a relativistic jet closely aligned with the line of sight. This implies the existence of a parent population of sources with a misaligned jet, that have been identified with low-power radiogalaxies. The spectrum of BL Lacs, dominated by non-thermal emission over the whole electromagnetic range, together with bright compact radio cores, high luminosities, rapid and large amplitude flux variability at all frequencies and strong polarization make these sources an optimal laboratory for high energy astrophysics. A most distinctive characteristic of the class is the weakness or absence of spectral lines, that historically hindered the identification of their nature and ever thereafter proved to be a hurdle in the determination of their distance. In this paper we review the main observational facts that contribute to the present basic interpretation of this class of active galaxies. We overview the history of the BL Lac objects research field and their population as it emerged from multi-wavelength surveys. The properties of the flux variability and polarization, compared with those at radio, X-ray and gamma-ray frequencies, are summarized together with the present knowledge of the host galaxies, their environments, and central black hole masses. We focus this review on the optical observations, that played a crucial role in the early phase of BL Lacs studies, and, in spite of extensive radio, X-ray, and recently gamma-ray observations, could represent the future major contribution to the unveiling of the origin of these sources. In particular they could provide a firm conclusion on the long debated issue of the cosmic evolution of this class of active galactic nuclei and on the connection between formation of supermassive black holes and relativistic jets.

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The X-ray jet and halo of PKS 0521−365

Cited by 46 publications

References 30 publications

X‐Ray Emission Properties of Large‐Scale Jets, Hot Spots, and Lobes in Active Galactic Nuclei

X‐Ray Emission Properties of Large‐Scale Jets, Hot Spots, and Lobes in Active Galactic Nuclei

Detection of Optical Synchrotron Emission from the Radio Jet of 3C 279

An optical view of BL Lacertae objects

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