We report results of the { { } ^ { 12 } CO } ( J = 3 - 2 ) and { HCO ^ { + } } ( J = 4 - 3 ) observations of the W40 H ii region with the ASTE 10 m telescope ( HPBW \simeq 22 \arcsec ) to search for molecular outflows and dense clumps .
We found that the velocity field in the region is highly complex , consisting of at least four distinct velocity components at V _ { LSR } \simeq 3 , 5 , 7 , and 10 km s ^ { -1 } .
The \sim 7 km s ^ { -1 } component represents the systemic velocity of cold gas surrounding the entire region , and causes heavy absorption in the { { } ^ { 12 } CO } spectra over the velocity range 6 \lesssim V _ { LSR } \lesssim 9 km s ^ { -1 } .
The \sim 5 and \sim 10 km s ^ { -1 } components exhibit high { { } ^ { 12 } CO } temperature ( \gtrsim 40 K ) and are found mostly around the H ii region , suggesting that these components are likely to be tracing dense gas interacting with the expanding shell around the H ii region .
Based on the { { } ^ { 12 } CO } data , we identified 13 regions of high velocity gas which we interpret as candidate outflow lobes .
Using the { HCO ^ { + } } data , we also identified six clumps and estimated their physical parameters .
On the basis of the ASTE data and near-infrared images from 2MASS , we present an updated three-dimensional model of this region .
In order to investigate molecular outflows in W40 , the SiO ( J = 1 - 0 , v = 0 ) emission line and some other emission lines at 40 GHz were also observed with the 45 m telescope at the Nobeyama Radio Observatory , but they were not detected at the present sensitivity .