During the first three observing runs of the Advanced gravitational-wave detector network , the LIGO/Virgo collaboration detected several black hole binary ( BHBH ) mergers .
As the population of detected BHBH mergers grows , it will become possible to constrain different channels for their formation .
Here we consider the chemically homogeneous evolution ( CHE ) channel in close binaries , by performing population synthesis simulations that combine realistic binary models with detailed cosmological calculations of the chemical and star-formation history of the Universe .
This allows us to constrain population properties , as well as cosmological and aLIGO detection rates of BHBH mergers formed through this pathway .
We predict a BHBH merger rate at redshift zero of 5.8 \hskip { 2.845276 pt } \textrm { Gpc } ^ { -3 } \textrm { yr } ^ { -1 } through the CHE channel , to be compared with aLIGO ’ s measured rate of { 53.2 } _ { -28.2 } ^ { +55.8 } \hskip { 2.845276 pt } \text { Gpc } ^ { -3 } \text { yr } ^ { -1 } , and find that eventual merger systems have BH masses in the range 17 - 43 \hskip { 2.845276 pt } \textrm { M } _ { \odot } below the pair-instability supernova ( PISN ) gap , and > 124 \hskip { 2.845276 pt } \textrm { M } _ { \odot } above the PISN gap .
We further investigate the effects of momentum kicks during black hole formation , calculate cosmological and magnitude limited PISN rates and investigate the effects of high-redshift deviations in the star formation rate .
We find that momentum kicks tend to increase delay times of BHBH systems , and our magnitude limited PISN rate estimates indicate that current deep surveys should be able to detect such events .
Lastly , we find that our cosmological merger rate estimates change by at most \sim 8 \% for mild deviations of the star formation rate in the early Universe , and by up to \sim 40 \% for extreme deviations .