An updated model for the Perseus Spiral Arm from Trigonometric Parallax and 3-dimensional kinematic distances of distant massive stars

We report trigonometric parallaxes and proper motions for three water masers and one methanol maser obtained with the VLBA as part of the BeSSeL Survey. Incorporating these parallaxes with 3-dimensional kinematic distances, we refine the position and pitch angle of the Perseus spiral arm in the 1${}^{\mathrm{s}\mathrm{t}}$ Galactic quadrant. Extrapolating the Perseus and Sagittarius arm locations to beyond the Galactic Center, we find that they intersect at an approximate Galactocentric azimuth of ${200}^{\circ }$ and radius of $5.6$~kpc.