Lunch talk on Apr. 22nd, 2019
Testing star formation rate models: the internal structures and star formation activities in the Galactic giant molecular clouds
Speaker: 张淼淼（马克斯·普朗克天文研究所）/ Miaomiao Zhang (Max Planck Institute for Astronomy)
Venue: The 3rd floor, SWIFAR Building
Time: 12:30 PM, Monday, 22nd April, 2019
How to understand and model the star formation rate (SFR) is a key question of star formation theory. The current view of galaxy formation and evolution relies on the ability to include small-scale star formation process into the models. The commonly-used SFR models comprise empirical relations and analytic models. Previous tests of SFR models mainly focus on the scale of galaxies based on extragalactic studies. Recently, studies have begun to test SFR models in our own Galaxy, but mainly at the scale of the most nearby clouds or with samples that are heavily biased by the massive star forming regions with high SFR. We have developed a new method to apply the near-infrared extinction mapping technique to the distant molecular clouds located in the Galactic plane, which can be used to investigate the internal structures of the giant molecular clouds (GMCs). We also develop a new method to estimate the SFRs of molecular clouds based on YSO counting. As a first test, we applied this method to about 50 giant molecular filaments (GMFs) and obtained their SFRs. Combining with the gas mass derived using CO survey data, we also tested several star formation relations in GMFs. We detect a significant correlation between SFR and dense gas mass for GMFs, indicating that the dense gas mass could be an important parameter in controlling the SFR of GMFs. In the near future, we plan to test the common SFR models in a large sample of GMCs located in the inner Galactic plane, which will fill the gap in between the scales of galaxies and nearby clouds and offer a comprehensive view of the relations between star formation process and cloud properties.