National Astronomical Observatory of Japan

Triggered Cluster Formation by the Dynamical Interactions of the Dense Molecular Gas : an Observational Study Using the 45m Telescope

| Science

This figure indicates the maps of the four objects, which are triggered by the dynamical interaction of the dense gas components.The young clusters (Background: the data of near Infrared observations) formed between the two dense gas components (red and blue contours).

The team led by Aya Higuchi, a researcher of ALMAJ, and Ryohei Kawabe, a professor of the Nobeyama Radio Observatory has carried out a detailed survey of 14 embedded clusters (young phases of open clusters). They have used the 45m telescope at the Nobeyama Radio Observatory and observed radio waves coming from "dense molecular gas" surrounding these stellar clusters. It is further known that stars form in groups (or clusters), but the exact formation and evolution processes and the relation to the surrounding environment are still not completely understood.

From this survey, they have discovered that four out of 14 objects are triggered by the dynamical interactions of the dense gas components (clump-clump collision). In the previous studies, the fraction of star formation triggered by these collisions may be low in our Galaxy.

However, their results show that there are many more possibilities of the triggered cluster formation by the clump-clump collision, which might occur inside the giant molecular clouds. Moreover, their results give the hints to understand the formation mechanism of open clusters within our Galaxy.

In the future, they will investigate the detailed structures of these objects with ALMA (Atacama Large Millimeter/submillimeter Array), which have 100 times the resolution of that of their data.