Using a population synthesis approach , we compute the total merger rate in the local Universe for double neutron stars , double black holes , and black hole – neutron star binaries .
These compact binaries are the prime source candidates for gravitational-wave detection by LIGO and VIRGO .
We account for mergers originating both from field populations and from dense stellar clusters , where dynamical interactions can significantly enhance the production of double compact objects .
For both populations we use the same treatment of stellar evolution .
Our results indicate that the merger rates of double neutron stars and black hole – neutron star binaries are strongly dominated by field populations , while merging black hole binaries are formed much more effectively in dense stellar clusters .
The overall merger rate of double compact objects depends sensitively on the ( largely unknown ) initial mass fraction contained in dense clusters ( f _ { cl } ) .
For f _ { cl } \lesssim 0.0001 , the Advanced LIGO detection rate will be dominated by field populations of double neutron star mergers , with a small but significant number of detections \sim 20 yr ^ { -1 } .
However for a higher mass fraction in clusters , f _ { cl } \gtrsim 0.001 , the detection rate will be dominated by numerous mergers of double black holes originating from dense clusters , and it will be considerably higher , \sim 25 - 300 yr ^ { -1 } .
In addition , we show that , once mergers of double black holes are detected , it is easy to differentiate between systems formed in the field and in dense clusters , since the chirp mass distributions are strikingly different .
If significant field populations of double black hole mergers are detected , this will also place very strong constraints on common envelope evolution in massive binaries .
Finally , we point out that there may exist a population of merging black hole binaries in intergalactic space .