We have performed a set of simulations of expanding , spherically symmetric nebulae inflated by winds from accreting black holes in ultraluminous X-ray sources ( ULXs ) .
We implemented a realistic cooling function to account for free-free and bound-free cooling .
For all model parameters we considered , the forward shock in the interstellar medium becomes radiative at a radius \sim 100 pc .
The emission is primarily in the optical and UV , and the radiative luminosity is about 50 % of the total kinetic luminosity of the wind .
In contrast , the reverse shock in the wind is adiabatic so long as the terminal outflow velocity of the wind v _ { w } \gtrsim 0.003 c .
The shocked wind in these models radiates in X-rays , but with a luminosity of only \sim 10 ^ { 35 } { erg s ^ { -1 } } .
For wind velocities v _ { w } \lesssim 0.001 c , the shocked wind becomes radiative , but it is no longer hot enough to produce X-rays .
Instead it emits in optical and UV , and the radiative luminosity is comparable to 100 % of the wind kinetic luminosity .
We suggest that measuring the optical luminosities and putting limits on the X-ray and radio emission from shock-ionized ULX bubbles may help in estimating the mass outflow rate of the central accretion disk and the velocity of the outflow .