The past and ongoing gravitational wave detections have fostered a wide interest in understanding the formation of binary black holes (BBHs). Several formation scenarios have been proposed, including the evolution of isolated massive binaries. While most of the observed merging black holes are at cosmological distances, and thus likely at low metallicity, the Small Magellanic Cloud (SMC) provides a unique laboratory to probe the binary scenario thanks to its rich massive star population and low metallicity. In this work, we provide comprehensive synthetic SMC populations of massive binary stars throughout all their different evolutionary stages, based on a dense grid of more than 50,000 detailed binary evolution models.
Our models well reproduce the observed Wolf-Rayet (WR) star + main sequence (MS) star binaries in the SMC (7 predicted), and we predict ~200 BH+MS star binaries, mostly associated with Be/Oe stars, which are so far undetected. The BH+MS binaries, if massive enough, may form BH+WR binaries. We find a high BH companion fraction for WR stars and predict 2-3 BH+WR binaries in the SMC. Our prediction on merging BBHs is sensitive to several model assumptions. The main features of the observed merging BBH population can be reproduced by our model, with common envelope evolution and stable mass transfer evolution contributing about equally. In conclusion, while our model in part agrees with the observed populations, it also raises new questions. In particular, there is an apparent lack of long-period massive evolved binaries with WR or BH components.
BIO
徐啸天博士，目前于Argelander-Institut fir Astronomie，波恩大学，德国，从事大质量双星演化、X射线双星、致密天体、以及双黑洞并合产生的引力波事件相关研究。在波恩大学Norbert Langer教授的指导下获得博士学位。之前于南京大学天文与空间科学学院获得硕士学位，研究X射线双星相关课题，导师为李向东教授。
Host: Zhuo Chen
