Dynamical formation of the GW190814 merger
  We investigate the possible dynamical origin of GW190814, a gravitational
wave (GW) source discovered by the LIGO-Virgo-Kagra collaboration (LVC)
associated with a merger between a stellar black hole (BH) with mass $23.2$
M$_\odot$ and a compact object, either a BH or a neutron star (NS), with mass
$2.59$ M$_\odot$. Using a database of 240,000 $N$-body simulations modelling
the formation of NS-BH mergers via dynamical encounters in dense clusters, we
find that systems like GW190814 are likely to form in young, metal-rich
clusters. Our model suggests that a little excess ($\sim 2-4\%$) of objects
with masses in the range $2.3-3$ M$_\odot$ in the compact remnants mass
spectrum leads to a detection rate for dynamically formed "GW190814 -like"
mergers of $\Gamma_{\rm GW190814} \simeq 1-6$ yr Gpc$^{-3}$, i.e. within the
observational constraints set by the GW190814 discovery, $\Gamma_{\rm LVC} \sim
1-23$ yr Gpc$^{-3}$. Additionally, our model suggests that $\sim 1.8-4.8\%$ of
dynamical NS-BH mergers are compatible with GW190426\_152155, the only
confirmed NS-BH merger detected by the LVC. We show that the relative amount of
light and heavy NS-BH mergers can provide clues about the environments in which
they developed.
