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|a Kharb, Preeti
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|a MIT Kavli Institute for Astrophysics and Space Research
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|a Marshall, Herman Lee
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|a Lister, Matthew L.
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|a Hogan, Brandon S.
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|a Marshall, Herman
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|a CHANDRA AND HST IMAGING OF THE QUASARS PKS B0106+013 AND 3C 345: INVERSE COMPTON X-RAYS AND MAGNETIZED JETS
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|b IOP Publishing,
|c 2015-02-25T14:08:38Z.
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|z Get fulltext
|u http://hdl.handle.net/1721.1/95505
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|a We present results from deep (~70 ks) Chandra/ACIS observations and Hubble Space Telescope (HST) Advanced Camera for Surveys F475W observations of two highly optically polarized quasars belonging to the MOJAVE blazar sample, viz., PKS B0106+013 and 1641+399 (3C 345). These observations reveal X-ray and optical emissions from the jets in both sources. X-ray emission is detected from the entire length of the 0106+013 radio jet, which shows clear bends or wiggles-the X-ray emission is brightest at the first prominent kiloparsec jet bend. A picture of a helical kiloparsec jet with the first kiloparsec-scale bend representing a jet segment moving close(r) to our line of sight, and getting Doppler boosted at both radio and X-ray frequencies, is consistent with these observations. The X-ray emission from the jet end, however, peaks at about 0[" over .]4 (~3.4 kpc) upstream of the radio hot spot. Optical emission is detected both at the X-ray jet termination peak and at the radio hot spot. The X-ray jet termination peak is found upstream of the radio hot spot by around 0[" over .]2 (~1.3 kpc) in the short projected jet of 3C 345. HST optical emission is seen in an arc-like structure coincident with the bright radio hot spot, which we propose is a sharp (apparent) jet bend instead of a terminal point, that crosses our line of sight and consequently has a higher Doppler beaming factor. A weak radio hot spot is indeed observed less than 1'' downstream of the bright radio hot spot, but has no optical or X-ray counterpart. By making use of the parsec-scale radio and the kiloparsec-scale radio/X-ray data, we derive constraints on the jet Lorentz factors (Γ[subscript jet]) and inclination angles (θ): for a constant jet speed from parsec to kiloparsec scales, we obtain a Γ[subscript jet] of ~70 for 0106+013 and ~40 for 3C 345. On relaxing this assumption, we derive a Γ[subscript jet] of ~2.5 for both the sources. Upper limits on θ of ~13° are obtained for the two quasars. Broadband (radio-optical-X-ray) spectral energy distribution (SED) modeling of individual jet components in both quasars suggests that the optical emission is from the synchrotron mechanism, while the X-rays are produced via the inverse Compton mechanism from relativistically boosted cosmic microwave background seed photons. The locations of the upstream X-ray termination peaks strongly suggest that the sites of bulk jet deceleration lie upstream (by a few kiloparsecs) of the radio hot spots in these quasars. These regions are also the sites of shocks or magnetic field dissipation, which reaccelerate charged particles and produce high-energy optical and X-ray photons. This is consistent with the best-fit SED modeling parameters of magnetic field strength and electron power-law indices being higher in the jet termination regions compared to the cores. The shocked jet regions upstream of the radio hot spots, the kiloparsec-scale jet wiggles and a "nose cone"-like jet structure in 0106+013, and the V-shaped radio structure in 3C 345, are all broadly consistent with instabilities associated with Poynting-flux-dominated jets. A greater theoretical understanding and more sensitive numerical simulations of jets spanning parsec to kiloparsec scales are needed, however, to make direct quantitative comparisons.
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|a United States. National Aeronautics and Space Administration (Chandra X-ray Observatory (U.S.) Award G09-0128X)
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|a en_US
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|a Article
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|t The Astrophysical Journal
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