The radio–ultraviolet spectral energy distribution of the jet in 3C 273

Jester, Sebastian; Röser, H.-J.; Meisenheimer, K.; Perley, R. A.

doi:10.1051/0004-6361:20047021

Cited by 70 publications

(133 citation statements)

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“…In 3C 273, Jester et al (2005) have already shown that only knots A and B1 have X-ray indices similar to their radio indices (which is required for IC/CMB), so our "combined knot" scenario includes only these two knots. For PKS 0637-752, we use all the bright X-ray knots just before the turn in the jet (wk7.8, wk8.9, wk9.7, and wk10.6) where one might assume that some deceleration likely takes place.…”

Section: Results: Testing the Ic/cmb Modelmentioning

confidence: 98%

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Ruling Out Ic/CMB X-Rays in PKS 0637-752 and the Implications for Tev Emission From Large-Scale Quasar Jets

Meyer

Georganopoulos

Sparks

et al. 2015

ApJ

130

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The Chandra X-ray observatory has discovered dozens of resolved, kiloparsec-scale jets associated with powerful quasars in which the X-ray fluxes are observed to be much higher than the expected level based on the radio-optical synchrotron spectrum. The most popular explanation for the anomalously high and hard X-ray fluxes is that these jets do not decelerate significantly by the kiloparsec scale, but rather remain highly relativistic (Lorentz factors Γ ∼ 10). By adopting a small angle to the line of sight, the X-rays can thus be explained by inverse Compton upscattering of cosmic microwave background (CMB) photons (IC/CMB), where the observed emission is strongly Doppler boosted. Using over six years of Fermi monitoring data, we show that the expected hard, steady gamma-ray emission implied by the IC/CMB model is not seen in PKS 0637-752, the prototype jet for which this model was first proposed. IC/CMB emission is thus ruled out as the source of the X-rays, joining recent results for the jets in 3C 273 (using the same method) and PKS 1136-135 (using UV polarization). We further show that the Fermi observations give an upper limit of δ < 6.5 for the four brightest X-ray knots of PKS 0637-752, and derive an updated limit of δ < 7.8 for knots A and B1 of 3C 273 (assuming equipartition). Finally, we discuss the fact that high levels of synchrotron X-ray emission in a slow jet will unavoidably lead to a level of angle-integrated TeV emission which exceeds that of the TeV BL Lac class.

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Section: Results: Testing the Ic/cmb Modelmentioning

confidence: 98%

“…We have also measured updated radio fluxes based on a re-analysis of archival and new ATCA data at 4.8, 8.4, and 17.8 GHz (first published in Godfrey et al 2012b). For 3C 273, data is taken from Jester et al (2005Jester et al ( , 2006 and Uchiyama et al (2006) and references therein.…”

Section: Results: Testing the Ic/cmb Modelmentioning

confidence: 99%

Ruling Out Ic/CMB X-Rays in PKS 0637-752 and the Implications for Tev Emission From Large-Scale Quasar Jets

Meyer

Georganopoulos

Sparks

et al. 2015

ApJ

130

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“…Left: Knot A in 3C 273 jet in radio and optical frequencies (from Jester et al 2005). Right: Different components of the knot K25 in 3C 120 jet in X-ray frequencies (from Harris et al 2004).…”

Section: Figurementioning

confidence: 99%

Radiative Processes In Extragalactic Large-Scale Jets

Stawarz¹

2005

AIP Conference Proceedings

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Abstract. About one thousand extragalactic large-scale jets are known, and a few tens of them are confirmed sources of infrared, optical, or X-ray photons. Multiwavelength emission comming directly from these outflows is always non-thermal in origin. This fact constitutes a primary difficulty in extracting unknown parameters of large-scale jets, since the non-thermal featureless continua do not allow to infer undoubtfully (or even at all) bulk velocities and composition of the radiating plasma. In addition, arcsecond spatial resolution, limited sensitivity and narrow energy bands of the best high-frequency telescopes like Spitzer, Hubble and Chandra, preclude precise constraints on the spectral and morphological properties of the discussed objects. Nevertheless, new multiwavelength observations have substantially enriched our knowledge on extragalactic large-scale jets, in many aspects, however, by means of challenging previous predictions and expectations. In this short contribution I will concentrate on the following issue: what can be learned by analyzing broad-band emission of the discussed objects about particle acceleration processes acting thereby and about jet internal parameters.Keywords: acceleration of particles -radiation mechanisms: non-thermal -galaxies: jets PARTICLE ACCELERATION PROCESSESPolarization and power-law spectral distribution of radio emission observed from extragalactic large-scale jets imply its synchrotron origin, and thus a power-law energy distribution of the radiating ultrarelativistic electrons. Radio spectral indices are concentrated around α R ∼ 0.75 (see, e.g., Kataoka & Stawarz 2005). This value is not strictly predicted by any particular model of particle acceleration applied to the discussed objects. For example, assuming the 'universal' shock-like particle spectrum n e (γ) ∝ γ −2 usually considered in this context, where γ is the particle Lorentz factor, one expects the synchrotron continuum of the form S ν ∝ ν −α with the spectral index α = 0.5 in a weak cooling regime, and α = 1.0 in a strong synchrotron (expected to be dominant) cooling regime. The situation is therefore that even the observed radio spectral properties of the large-scale jet are not consistent with the simplest scenarios for the evolution of the electron energy distribution. Taking into account the complexity of the jet phenomenon we should not in fact expect the simplest models to be realistic. Meanwhile, the 'injection' electron spectrum (not affected by spectral ageing) remains elusive. One can hope that by performing observations at low radio frequencies such a spectrum will be revealed, and thus strong observational constraints will help to develop the appropriate theoretical model. Indeed, Young et al. (2005) found that the radio data for FR I sources imply n e (γ) ∝ γ −2.1 . Such a spectrum may be interpreted as manifestation of the effects con-

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“…For a recent review of KHI in YSO jets see the article by Trussoni (2009). While radiative cooling is not thought to be important on the relativistic jets there are still some interesting similarities in morphology between YSO jets and AGN jets, e.g., compare the knots, twists, asymmetries and bow shock structures in HH 212 (Zinnecker et al 1998) and HH 111 (Reipurth et al 1997;Reipurth et al 1999) with the knots and twists in 3C 273 (Jester et al 2005;Uchiyama et al 2006) and the twists and bow shock structures in Hercules A (Dreher & Feigelson 1984). Thus, the following discussion restricted to nonradiative KHI and CDI work will also be relevant to the YSO jets.…”

Section: Introductionmentioning

confidence: 99%

The stability of astrophysical jets

Hardee

2010

Proc. IAU

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Abstract. Jets are produced by young stellar objects (YSOs), by black hole binary star system "microquasars" (µQSOs), by active galactic nuclei (AGN), are associated with neutron stars and pulsar wind nebulae (PWNe), and are thought responsible for the gamma-ray bursts (GRBs). An understanding of these outflows must include how they are launched and collimated into jets, and how they propagate to large distances. Jets be they Poynting flux and/or kinetic flux dominated are current driven (CD) and/or Kelvin-Helmholtz (KH) velocity shear driven unstable. Here I present some of the work that is leading to a better understanding of the properties required for the observed relative stability of astrophysical jets.

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The radio–ultraviolet spectral energy distribution of the jet in 3C 273

Cited by 70 publications

References 44 publications

Ruling Out Ic/CMB X-Rays in PKS 0637-752 and the Implications for Tev Emission From Large-Scale Quasar Jets

Ruling Out Ic/CMB X-Rays in PKS 0637-752 and the Implications for Tev Emission From Large-Scale Quasar Jets

Radiative Processes In Extragalactic Large-Scale Jets

The stability of astrophysical jets

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