学术报告第151期：The Star Formation Rate of Molecular Clouds in Supernova-Driven Turbulence

主讲人 (Speaker): 

Paolo Padoan

主讲人单位 (Speaker's Institute): 

巴塞罗那大学

邀请人 (Invited by): 

潘刘彬

时间 (Time): 

星期四, 2019/11/14 - 15:00 to 16:00

地点 (Location): 

珠海校区海滨红楼17栋107 (Rm 107, Red House 17)

摘要 (Abstract): 

We compute the star-formation rate (SFR) in molecular clouds (MCs) that originate ab initio in a high-resolution simulation of supernova-driven turbulence. Because of the large number of well-resolved clouds with self-consistent boundary and initial conditions, we obtain a large range of cloud physical parameters with realistic statistical distributions, which is an unprecedented sample of star-forming regions to test SFR models and to interpret observational surveys. We confirm the dependence of the SFR per free-fall time, SFRff, on the virial parameter, α vir, found in previous simulations, and compare a revised version of our turbulent fragmentation model with the numerical results. The dependences on Mach number, { M }, gas to magnetic pressure ratio, β, and compressive to solenoidal power ratio, χ at fixed α vir are not well constrained, because of random scatter due to time and cloud-to-cloud variations in SFRff. We find that SFRff in MCs can take any value in the range of 0 ≤ SFRff ≲ 0.2, and its probability distribution peaks at a value of SFRff ≈ 0.025, consistent with observations. The values of SFRff and the scatter in the SFRff-α virrelation are consistent with recent measurements in nearby MCs and in clouds near the Galactic center. Although not explicitly modeled by the theory, the scatter is consistent with the physical assumptions of our revised model and may also result in part from a lack of statistical equilibrium of the turbulence, due to the transient nature of MCs.

主讲人简介 (Speaker's CV): 

教育背景 PhD in Astrophysics, Niels Bohr Institute - University of Copenhagen, (1997). Degree in Astronomy, Università degli Studi di Padova, (1992). 工作经历 ICREA Research Professor at UB (Universitat de Barcelona) - Physics (2010-Present). Associate Professor (tenured) at UCSD (University of California, San Diego) - Physics (2007-Present). Assistant Professor at UCSD (University of California, San Diego) - Physics (2003-2007). National Research Council Associate, Jet Propulsion Laboratory - NASA/Caltech. (2001-2003). Postdoctoral Fellow, Harvard University. (1999-2001). CONACYT Fellow, Instituto Nacional de Astrofisica, Optica y Electronica, Puebla, Mexico. (1998-1999). 研究方向 Star Formation, Astrophysical Turbulence, Planet Formation