Host galaxy properties of mergers of stellar binary black holes and their implications for advanced LIGO gravitational wave sources

Understand

Understanding the host galaxy properties of stellar binary black hole (SBBH) mergers is important for revealing the origin of the SBBH gravitational-wave sources detected by advanced LIGO and helpful for identifying their electromagnetic counterparts.

• Here we present a comprehensive analysis of the host galaxy properties of SBBHs by implementing semi-analytical recipes for SBBH formation and merger into cosmological galaxy formation model.
• If the time delay between SBBH formation and merger ranges from $\la$\,Gyr to the Hubble time, SBBH mergers at redshift $z\la0.3$ occur preferentially in big galaxies with stellar mass $M_*\ga2\times10^{10}\msun$ and metallicities $Z$ peaking at $\sim0.6Z_\odot$.
• However, the host galaxy stellar mass distribution of heavy SBBH mergers ($M_{\bullet\bullet}\ga50\msun$) is bimodal with one peak at $\sim10^9\msun$ and the other peak at $\sim2\times10^{10}\msun$.