Multifrequency Observations of the Jet of 3C 273

Harris

Marshall

et al. 2006

ApJ

124

167

The jet in 3C 273 is a high-power quasar jet with radio, optical, and X-ray emission, whose size and brightness allow a detailed study of the emission processes acting in it. We present deep Chandra observations of this jet and analyze the spectral properties of the jet emission from radio through X-rays. We find that the X-ray spectra are significantly softer than the radio spectra in all regions of the bright part of the jet, except for the first bright ''knot A,'' ruling out a model in which the X-ray emission from the entire jet arises from beamed inverse Compton scattering of cosmic microwave background photons in a single-zone jet flow. Within two-zone jet models, we find that a synchrotron origin for the jet's X-rays requires fewer additional assumptions than an inverse Compton model, especially if velocity shear leads to efficient particle acceleration in jet flows.

Section: Discussion: Implications Of the New Seds For The X-ray Emissmentioning

confidence: 99%

Section: Discussion: Implications Of the New Seds For The X-ray Emissmentioning

confidence: 99%

NewChandraObservations of the Jet in 3C 273. I. Softer X‐Ray than Radio Spectra and the X‐Ray Emission Mechanism

Harris

Marshall

et al. 2006

ApJ

124

167

“…3 makes the discrepancy smaller. In addition, the emission region becomes wider towards longer wavelengths, an effect already noticeable in the near-infrared K band ) and attributed to a "backflow" (Röser et al 1996). The presence of such a steepspectrum, diffuse component more extended than the jet channel might also explain the discrepancy.…”

Section: The Spectral Index At Hst Resolutionmentioning

confidence: 98%

HST optical spectral index map of the jet of 3C 273

Röser

Meisenheimer

et al. 2001

A&A

Self Cite

112

Abstract. We present HST images at 622 nm and 300 nm of the jet in 3C 273 and determine the run of the optical spectral index at 0. 2 along the jet. The smoothness of spectral index changes shows that the physical conditions are varying smoothly across the jet. There is no correlation between the optical flux and spectral index, as would be expected for relativistic electrons suffering strong cooling due to synchrotron emission. We find no evidence for localized acceleration or loss sites. This suggests that the spectral shape is not changing much throughout the jet. We show that relativistic beaming and/or sub-equipartition magnetic fields cannot remove the discrepancy between light-travel time along the jet and the lifetime of electrons emitting optical synchrotron radiation. We consider this further evidence in favour of a distributed electron acceleration process.

“…Due to its large angular extent of over 20 (≈60 kpc at z = 0.158 1 ) and its high surface brightness in the radio, optical and in X-rays, it is readily observable and serves as a sample case for the study of extragalactic jets. The high degree of optical polarisation (10%-20%; Röser & Meisenheimer 1991) and the overall agreement with the radio polarisation properties (Röser et al 1996) imply that the bulk of the jet's optical light is synchrotron emission from the same electron population responsible for the radio emission. However, the X-rays could be synchrotron emission from this same electron population only for regions A and B of the jet (Röser et al 2000;Marshall et al 2001).…”

Section: Introductionmentioning

confidence: 93%

X-rays from the jet in 3C 273: Clues from the radio–optical spectra

Röser

Meisenheimer

et al. 2002

A&A

Self Cite

Abstract.Using new deep VLA and HST observations of the large-scale jet in 3C 273 matched to 0. 3 resolution, we have detected excess near-ultraviolet emission (λ 300 nm) above a synchrotron cutoff spectrum accounting for the emission from radio through optical (λλ3.6 cm-620 nm). This necessitates a two-component model for the emission. The radio-optical-X-ray spectral energy distributions suggest a common origin for the UV excess and the X-rays from the jet.