We present results from deep ( \sim 70 ks ) Chandra ACIS observations and Hubble Space Telescope ( HST ) ACS F475W observations of two highly optically polarized quasars belonging to the MOJAVE ( Monitoring Of Jets in Active galactic nuclei with VLBA Experiments ) blazar sample , viz. , PKS B0106+013 and 1641+399 ( 3C 345 ) .
These observations reveal X-ray and optical emission 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 kpc jet bend .
A picture of a helical kpc jet with the first kpc-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 \farcs 4 ( \sim 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 \farcs 2 ( \sim 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 \arcsec downstream of the bright radio hot spot , but has no optical or X-ray counterpart .
By making use of the pc-scale radio and the kpc-scale radio/X-ray data , we derive constraints on the jet Lorentz factors ( \Gamma _ { jet } ) and inclination angles ( \theta ) : for a constant jet speed from pc- to kpc-scales , we obtain a \Gamma _ { jet } of \sim 70 for 0106+013 , and \sim 40 for 3C 345 .
On relaxing this assumption , we derive a \Gamma _ { jet } of \sim 2.5 for both the sources .
Upper limits on \theta of \sim 13 \arcdeg are obtained for the two quasars .
Broad-band ( radio-optical-X-ray ) spectral energy distribution 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 kpc ) 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 powerlaw indices being higher in the jet termination regions compared to the cores .
The shocked jet regions upstream of the radio hot spots , the kpc-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 kpc-scales are needed , however , to make direct quantitative comparsions .