Radio observation of molecular clouds around the W5-East triggered star-forming region

It is known that most of stars are formed as clusters (Lada & Lada 2003, ARAA 41, L57) and clusters are formed by triggering. However, the relationships of molecular clouds' conditions and properties of formed stars by triggering is not well studied. To clarify differences between triggered and spontaneous star formation through physical properties of molecular clouds (e.g. mass, density, morphology), we observed the W5-East HII region. The W5-East HII region is located at 2 kpc and has a 10 pc extent of HII region. This region has 3 Bright Rimmed Clouds (BRCs; Sugitani et al. 1991, ApJS 77, S59), which are interface between HII regions and molecular clouds, and known as sites of triggered star formation. The molecular clouds surround the W5-East (Karr et al. 2003, ApJ, 595, 900), thus we expect molecular clouds morphology is affected by the HII region and the cloud evolution is supposed to be dominated by the expanding HII region.