Recent works, e.g. Peuten et al. (2016) and Baumgradt & Sollima (2017), have been constraining the retention fraction of black holes (BHs) in globular clusters by comparing the degree of mass segregation with N-body simulations. They are consistent with an upper limit of the retention fraction being 50 % or less (e.g. 10 %). In this work we focus on direct simulations of the dynamics of BHs in star clusters, aiming to constrain the distribution of natal kicks which BHs receive during supernovae explosions. To do so, we modified the Aarseth's nbody6 code so that we can measure the retention fraction of BHs for a given set of parameters which are: the initial mass of a star cluster, the initial half-mass radius and σ, the value of the Maxwellian BH velocity kick distribution. We compare these direct N-body models with our analytic estimates and observational constraints derived by Peuten et al. (2016) and Baumgardt & Sollima (2017).
Based on Yan, Jerabkova, Kroupa (2017, A&A, in press): a Python3 module for computing the galaxy-wide initiall stellar mass function by integrating over a whole galaxy, parametrised by star formation rate and metallicity.