SIMBAD references

We have conducted a ¹³CO survey of a sample of 128 infrared color-selected intermediate-mass star-forming region (IM SFR) candidates. We utilized the Onsala 20 m telescope to observe ¹³CO (1-0) toward 67 northern IM SFRs, used the 12 m Atacama Pathfinder Experiment telescope to observe ¹³CO (2-1) toward 22 southern IM SFRs, and incorporated an additional 39 sources from the Boston University Five College Radio Astronomy Observatory Galactic Ring Survey which observed ¹³CO (1-0). We detect ¹³CO (1-0) in 58 of the 67 northern sources and ¹³CO (2-1) in 20 of the 22 southern sources. The mean molecular column densities and ¹³CO linewidths in the inner Galaxy are higher by factors of 3.4 and 1.5, respectively, than the outer Galaxy. We attribute this difference to molecular clouds in the inner Galaxy being more massive and hosting star forming regions with higher luminosities on average than the outer Galaxy. IM SFRs have mean a molecular column density of 7.89x10²¹/cm2, a factor of 3.1 lower than that for a sample of high-mass regions, and have a mean ¹³CO linewidth of 1.84 km/s, a factor of 1.5 lower than that for high-mass regions. We demonstrate a correlation between ¹³CO linewidth and infrared luminosity as well as between molecular column density and infrared luminosity for the entire sample of intermediate-mass and high-mass regions. IM SFRs appear to form in distinctly lower-density environments with mean linewidths and beam-averaged column densities a factor of several lower than high-mass star-forming regions.