Nobeyama 45 m Local Spur CO survey. I. Giant molecular filaments and cluster formation in the Vulpecula OB association

Abstract

We have performed new large-scale 12 CO, 13 CO, and C 18 O J =1-0 observations toward the Vulpecula OB association (l ∼ 60 • ) as part of the Nobeyama 45 m Local Spur CO survey project. Molecular clouds are distributed over ∼ 100 pc, with local peaks at the Sh 2-86, Sh 2-87, and Sh 2-88 high-mass star-forming regions in the Vulpecula complex. The molecular gas is associated with the Local Spur, which corresponds to the nearest inter-arm region located between the Local Arm and the Sagittarius Arm. We discovered new giant molecular filaments (GMFs) in Sh 2-86, with a length of ∼ 30 pc, width of ∼ 5 pc, and molecular mass of ∼ 4 × 10 4 M . We also found that Sh 2-86 contains the three velocity components at 22, 27, and 33 km s −1 . These clouds and GMFs are likely to be physically associated with Sh 2-86 because they have high 12 CO J = 2-1 to J = 1-0 intensity ratios and coincide with the infrared dust