Stellar-mass black holes in young massive and open stellar clusters and
  their role in gravitational-wave generation
  The dynamical processes involving stellar-remnant black holes (BH) in stellar
clusters has always drawn attention due to the BHs' potential in a number of
astrophysical phenomena, especially the dynamical formation of binary black
holes (BBH), which would potentially coalesce via radiation of gravitational
waves (GW). This study presents a preliminary set of evolutionary models of
compact stellar clusters with initial masses ranging over
$1.0\times10^4M_\odot-5.0\times10^4M_\odot$, and half-mass radius of 2 pc or 1
pc, that is typical for young massive and starburst clusters. They have
metallicities between $0.05Z_\odot-Z_\odot$. Including contemporary schemes for
stellar wind and remnant-formation, such model clusters are evolved, for the
first time, using the state-of-the-art direct N-body evolution program NBODY7,
until their dissolution or at least for 10 Gyr. That way, a self-regulatory
behaviour in the effects of dynamical interactions among the BHs, especially
while heating and expanding the cluster and self-depleting the BHs, is
demonstrated. The BBH mergers obtained here show a prominence in
triple-mediated mergers while being bound to the clusters, compared to those
occurring among the BBHs that are dynamically ejected from the clusters. This
is in contrast with earlier N-body computations and also with recent
Monte-Carlo method based ones. A broader mass spectrum of BHs and ejection of
BBHs generally of wider orbits and in lower numbers, for the cluster masses
explored here, might cause this which is yet to be fully understood. Among the
BBH coalescences obtained here, there are ones that resemble the detected
GW151226, LVT151012, and GW150914 events and also ones which are even more
massive. A preliminary estimate suggests few 10s - 100s of BBH coalescences per
year, originating due to dynamics in stellar clusters, that can be detected by
the LIGO at its design sensitivity.
