Maser and Molecular Line Surveys of 6.7GHz ClassII Methanol Maser Sources

Methanol maser sources are believed to represent the earliest evolutionary stage of massive star formation. Pandian et al. (2007) recently made a very sensitive blind survey of 6.7GHz ClassII methanol maser towards the Galacitic midplane ($35^{\circ}$<1<$55^{\circ}$ & |b|<$0.5^{\circ}$) and found 86 maser sources. We carried out 22GHz $H_2O$ and 44.0 GHz $CH_3OH$ maser line surveys of them with KVN 21m and various (CO (2-1), $^{13}CO$ (2-1), $^{13}CO$ (1-0), $C^{18}O$ (2-1), CS (2-1), $HCO^+$ (3-2) and HCN (3-2)) molecular line surveys with SRAO 6m and TRAO 14m. we will present the preliminary results and discuss the implications for massive star formation.