Figure 15
Figure 15: Contours of constant number of X-ray binaries as a function of the “Verbunt parameters”. Here Γ = ρ2r3c∕vc, γ = ρ∕vc, ρ is the average stellar density, rc is the core radius and vc the core velocity dispersion. Γ describes the two-body stellar encounter rate and γ describes the rate of encounters between a single binary with the stellar background. The squares represent the location of various Galactic globular clusters in the γ − Γ plane and the number in parentheses is the number of X-ray binaries observed in the cluster. Plot reproduced by permission from Banerjee and Ghosh [30], copyright by IOP.