Taiwan-led team makes astrophysics find

2015/05/22

A research team led by Taipei City-based Academia Sinica recently made a breakthrough in astrophysical research, shedding new light on understanding of the upper end of stellar molecular core mass functions.

Based on observations via the Atacama Large Millimeter/submillimeter Array, the team discovered the luminous OB cluster-forming massive molecular clump G33.92 plus 0.11, unveiling the fine molecular gas structures deeply embedded in the center of the parent molecular cloud. OB-type stars often exhibit signatures of activity, with associated variability and structure on a range of temporal and spatial scales.

The finding, published in the May 1 issue of The Astrophysical Journal, reveals for the first time an embedded giant coherent dense gas structure on a several light-year scale. It also provides a greatly simplified picture of overall cloud geometry and kinematics.

Team leader Liu Hau-yu, a postdoctoral researcher at the AS Institute of Astronomy and Astrophysics, said creation of young massive clusters and globular clusters has always been a fundamental question in astrophysical research.

“To form such complex systems, it is necessary for massive amounts of gas to be converted into stars with little loss before the gas is dispersed by stellar feedback,” he said, adding that this suggests such systems require a special geometry and dynamical evolution of the natal molecular cloud.

“ALMA observations show that this massive cluster-forming molecular cloud underwent a rapid global gravitation collapse, resulting in a flattened, dense rotating gas structure.”

In particular, Liu believes that gravitational instability led to the formation of several giant spiral arms, which further fragmented to form satellite dense molecular gas cores. “Spiral arms and gas cores act like a cradle, shielding the new star formations in the central and satellite dense molecular cores from the radiative and mechanical feedback of ambient stars.”

The team’s discovery is expected to pave the way for addressing the most important questions in the follow-up ALMA observations.

Partially funded by the ROC Ministry of Science and Technology, the project also involved researchers from Mexico, the U.K. and U.S.

Source: Taiwan Today (http://taiwantoday.tw/ct.asp?xItem=230638&ctNode=413)