H2CO and CO in 4 molecular clouds

More specifically, we look for the relationship among the H_2_CO, ^12^CO, and ^13^CO spectral lines. The four regions of MON R2 (60'x90'), S156 (50'x70'), DR17/L906 (40'x60'), and M17/M18 (70'x80') were observed for H_2_CO (beam 10'), H110{alpha} recombination (beam 10'), 6 cm continuum (beam 10'), ^12^CO (beam 1'), and ^13^CO (beam 1').

We compared the H_2_CO, ^12^CO, ^13^CO, and continuum distributions, and also the spectra line parameters of H_2_CO, ^12^CO, and ^13^CO. Column densities of H_2_CO, ^13^CO, and H_2_ were also estimated. We found out that the H_2_CO distribution is similar to the ^12^CO and the ^13^CO distributions on a large scale.