Resolving the Powerful Radio-loud Quasar at z~6
  We present high angular resolution imaging ($23.9 \times 11.3$ mas, $138.6
\times 65.5$ pc) of the radio-loud quasar PSO~J352.4034$-$15.3373 at $z=5.84$
with the Very Long Baseline Array (VLBA) at 1.54 GHz. This quasar has the
highest radio-to-optical flux density ratio at such a redshift, making it the
radio-loudest source known to date at $z \sim 6$. The VLBA observations
presented here resolve this quasar into multiple components with an overall
linear extent of 1.62 kpc ($0\rlap{.}{''}28$) and with a total flux density of
$6.57 \pm 0.38$ mJy, which is about half of the emission measured at a much
lower angular resolution. The morphology of the source is comparable with
either a radio core with a one-sided jet, or a compact or a medium-size
Symmetric Object (CSO/MSO). If the source is a CSO/MSO, and assuming an advance
speed of $0.2c$, then the estimated kinematic age is $\sim 10^4$ yr.
