Revealing the CMFs in the ONC regions and IRDCs

Speaker: Hideaki Takemura (Sokendai, *Student talk)


Stars are formed in dense cores in molecular clouds. Therefore, it is important to understand how dense cores form from parental molecular clouds to reveal star formation processes. The mass functions of dense cores (CMFs) are expected to have some information on the core formation and evolution processes. Many previous studies of CMFs with single-dish telescopes have suggested that the CMFs resemble the stellar initial mass functions (IMFs) toward nearby star-forming regions. However, recent ALMA observations of distant high-mass star-forming regions have revealed that the CMFs are different from the stellar IMFs and the CMFs in nearby star-forming regions. Thus, more observations with enough resolution and sensitivity are needed to understand the properties of CMFs. Toward a full understanding of the origin of CMFs, we study the CMFs in the Orion Nebula Cluster (ONC) region located in the nearest GMC, Orion A, and distant infrared dark clouds (IRDCs). In the ONC region, we compare the CMF and IMF and his study is the second case that compares the two functions in the same region. Then, we found that mass accretion from the surroundings to dense cores may play a crucial role in determining the final stellar masses of stars. Using the CMFs in the IRDCs in the early stages, we investigated the initial condition of high-mass star formation. In previous observations, temperatures of clumps are often used, but we derived CMFs with the temperature of individual cores derived from ammonia observations. In the presentation. From the preliminary results, the properties of CMFs with clump temperatures are similar to CMFs with individual core temperatures.