Distances to molecular clouds in the second Galactic quadrant

Abstract

We present distances to 76 medium-sized molecular clouds and an extra large-scale one in the second Galactic quadrant ($104.75^{\circ }<l<150.25^{\circ }$ and $|b|<5.25^{\circ }$), 73 of which are accurately measured for the first time. Molecular cloud samples are drawn from $l$-$b$-$V$ space ($-95<V_{\mathrm{LSR}}<25$ \kms) with the density-based spatial clustering of applications with noise (DBSCAN) algorithm, and distances are measured with the background-eliminated extinction-parallax (BEEP) method using extinctions and Gaia DR2 parallaxes. The range of measured distances to 76 molecular clouds is from 211 to 2631 pc, and the extra large-scale molecular cloud appears to be a coherent structure at about 1 kpc, across about 40° ($\sim$700 pc) in the Galactic longitude.

10 pages, 9 figures, accepted for pulication in A&A