We study a model of rapidly cooling shocked stellar winds in young massive clusters and estimate the circumstances under which secondary star formation , out of the reinserted winds from a first stellar generation ( 1G ) , is possible .
We have used two implementations of the model : a highly idealized computationally inexpensive spherically symmetric semi-analytic model , and a complex three-dimensional radiation-hydrodynamic simulations , and they are in a good mutual agreement .
The results confirm our previous findings that in a cluster with 1G mass 10 ^ { 7 } M _ { \odot } and half-mass radius 2.38 pc , the shocked stellar winds become thermally unstable , collapse into dense gaseous structures that partially accumulate inside the cluster , self-shield against ionizing stellar radiation and form the second generation ( 2G ) of stars .
We have used the semi-analytic model to explore a subset of the parameter space covering a wide range of the observationally poorly constrained parameters : the heating efficiency , \eta _ { \mathrm { he } } , and the mass loading , \eta _ { \mathrm { ml } } .
The results show that the fraction of the 1G stellar winds accumulating inside the cluster can be larger than 50 % if \eta _ { \mathrm { he } } \lesssim 10 % which is suggested by the observations .
Furthermore , for low \eta _ { \mathrm { he } } , the model provides a self-consistent mechanism predicting 2G stars forming only in the central zones of the cluster .
Finally , we have calculated the accumulated warm gas emission in the H30 \alpha recombination line , analyzed its velocity profile and estimated its intensity for super star clusters in interacting galaxies NGC4038/9 ( Antennae ) showing that the warm gas should be detectable with ALMA .