We report the results of large-scale mapping for 6-cm H2CO absorption lines at 4829.6594 MHz and H110α radio recombination line at 4.8 GHz towards Perseus Gaint Molecular Clouds on a grid of 6? ×3? with a pixel size of 10′× 10′ using the Nanshan 25-m radio telescope, valid three sigma signals were found in 185 out of 443 position.
The H2CO absorption line distribution of Perseus GMC has been sub divided in six sub-regions with approximate borders for each region using the H2CO line velocity map. A velocity gradient from the western to eastern portion of the cloud has been detected. The velocity dispersion map indicates that the velocity dispersion among Perseus GMC lies within a relatively low and small range.
We investigated morphologic relations among H2CO contours, 12CO, 13CO contours and 6-cm continuum brightness temperature found their peaks locate at the same position. Through multiple correlations this shows that these lines arise from similar physical environments and can equally be used to trace the star formation regions of the cloud. We ?nd that in the IC 348 region has the highest dust temperature and the lowest abundance, while the L 1455 region has the lowest dust temperature and the highest H2CO abundance. Accordingly, we suggest that the higher dust temperature and the lower abundance of IC 348 may arise from the same physical conditions a?ected by the H ii region.