Title: The high-performance N-body code PeTar for studying the dynamical evolution of massive star clusters and gravitational waves
Speaker: Long Wang (天文学教室/Department of Astronomy)
Binary black hole (BBH) mergers in dense stellar systems like globular clusters (GCs) are important sources for the gravitational waves detected by Advanced LIGO. Star-by-star N-body simulation is the most reliable method to understand the formation rate, mass ratio and orbital parameters of these BBHs. But it is very time-consuming to produce such a model because of the expensive computing. To overcome this bottleneck, I have developed a high-performance N-body code, PeTar. It is the fastest code for modelling massive star clusters with a large fraction of binaries. Using PeTar, we carried out a series of N-body models for massive star clusters, and found that the initial mass function significantly affects the long-term evolution of GCs and properties of BBH mergers, while primordial binaries have a weak influence. For low-mass open clusters with tidal streams, the stochastic sampling of IMF makes it impossible to predict their long-term evolution. In addition, we implement PeTar in a hydrodynamic code, Asura-bridge, which allows us to study the star cluster formation with the complexity from binary dynamics, gas and feedback of massive stars. With the benefit of highly accurate binary dynamics from PeTar, we found when massive stars form, the violent close interaction can easily eject them from the birth place and significantly affect the surrounding star formation. This may explain the multiple populations discovered in young star clusters like Orion nebular cluster. In summary, the PeTar code opens a new window to solve a variety of challenging N-body problems.
(This talk will be given online. Details will be announced via e-mail.)
hongo-astrotalks (at-sign) astron.s.u-tokyo.ac.jp