The quasar 3C 286 is one of two compact steep spectrum sources detected by the Fermi /LAT .
Here , we investigate the radio properties of the parsec ( pc ) -scale jet and its ( possible ) association with the \gamma -ray emission in 3C 286 .
The Very Long Baseline Interferometry ( VLBI ) images at various frequencies reveal a one-sided core–jet structure extending to the southwest at a projected distance of \sim 1 kpc .
The component at the jet base showing an inverted spectrum is identified as the core , with a mean brightness temperature of 2.8 \times 10 ^ { 9 } K. The jet bends at about 600 pc ( in projection ) away from the core , from a position angle of -135 ^ { \circ } to -115 ^ { \circ } .
Based on the available VLBI data , we inferred the proper motion speed of the inner jet as 0.013 \pm 0.011 mas yr ^ { -1 } ( \beta _ { app } = 0.6 \pm 0.5 ) , corresponding to a jet speed of about 0.5 c at an inclination angle of 48 ^ { \circ } between the jet and the line of sight of the observer .
The brightness temperature , jet speed and Lorentz factor are much lower than those of \gamma -ray-emitting blazars , implying that the pc-scale jet in 3C 286 is mildly relativistic .
Unlike blazars in which \gamma -ray emission is in general thought to originate from the beamed innermost jet , the location and mechanism of \gamma -ray emission in 3C 286 may be different as indicated by the current radio data .
Multi-band spectrum fitting may offer a complementary diagnostic clue of the \gamma -ray production mechanism in this source .