Parallaxes for Star-forming Regions in the Inner Perseus Spiral Arm

Abstract

Abstract We report trigonometric parallax and proper motion measurements of 6.7 GHz CH 3 OH and 22 GHz H 2 O masers in eight high-mass star-forming regions (HMSFRs) based on Very Long Baseline Array (VLBA) observations as part of the Bar and Spiral Structure Legacy (BeSSeL) Survey. The distances of these HMSFRs combined with their Galactic coordinates, radial velocities, and proper motions, allow us to assign them to a segment of the Perseus arm with ℓ ≲ 70°. These HMSFRs are clustered in Galactic longitude from ≈30° to ≈50° neighboring a dearth of such sources between longitudes ≈50° to ≈90°.