# Formation of the first three gravitational-wave observations through isolated binary evolution

## TL;DR

This paper demonstrates that the first three gravitational-wave detections from binary black hole mergers can be explained by a single isolated binary evolution channel, emphasizing the role of low-metallicity environments and common envelope phases.

## Contribution

It shows that all three observed events can be explained by classical isolated binary evolution with a common envelope, using the COMPAS population synthesis code.

## Key findings

- All three events likely formed in low-metallicity environments.
- Progenitor binaries had total masses exceeding 160, 60, and 90 solar masses.
- A single evolutionary channel can account for multiple gravitational-wave events.

## Abstract

During its first 4 months of taking data, Advanced LIGO has detected gravitational waves from two binary black hole mergers, GW150914 and GW151226, along with the statistically less significant binary black hole merger candidate LVT151012. We use our rapid binary population synthesis code COMPAS to show that all three events can be explained by a single evolutionary channel -- classical isolated binary evolution via mass transfer including a common envelope phase. We show all three events could have formed in low-metallicity environments (Z = 0.001) from progenitor binaries with typical total masses $\gtrsim 160 M_\odot$, $\gtrsim 60 M_\odot$ and $\gtrsim 90 M_\odot$, for GW150914, GW151226, and LVT151012, respectively.