Fig. 2.
H2 column density map of the M 17 SWex cloud, which was derived by SED fitting of the Herschel archival data (160, 250, 350, and |$500\, \mu$|m). The reference areas that were used to subtract the background emission of the galactic plane to construct the column density map are shown by five dashed green boxes. The subtraction was simply performed by 2D linear-plain fitting using the flux of these five areas to exclude the background emission from the galactic plane. The contour lines of 7.0 × 1021 cm−2 are shown by thin white lines. (Color online)
