Spiral-wave wind for the blue kilonova. (arXiv:1907.04872v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Nedora_V/0/1/0/all/0/1">Vsevolod Nedora</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bernuzzi_S/0/1/0/all/0/1">Sebastiano Bernuzzi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Radice_D/0/1/0/all/0/1">David Radice</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perego_A/0/1/0/all/0/1">Albino Perego</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Endrizzi_A/0/1/0/all/0/1">Andrea Endrizzi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ortiz_N/0/1/0/all/0/1">N&#xe9;stor Ortiz</a>

The AT2017gfo kilonova counterpart of the binary neutron star merger event
GW170817 was characterized by an early-time bright peak in optical and UV
bands. Such blue kilonova is commonly interpreted as a signature of weak
$r$-process nucleosynthesis in a fast expanding wind whose origin is currently
debated. Numerical-relativity simulations with microphysical equations of
state, approximate neutrino transport, and turbulent viscosity reveal a new
mechanism that can power the blue kilonova. Spiral density waves in the remnant
generate a characteristic wind of mass ${sim}10^{-2}~M_{odot}$ and velocity
${sim}0.2$c. The ejected material has electron fraction mostly distributed
above $0.25$ being partially reprocessed by hydrodynamic shocks in the
expanding arms. The combination of dynamical ejecta and spiral-wave wind can
account for solar system abundances of $r$-process elements and early-time
observed light curves.

The AT2017gfo kilonova counterpart of the binary neutron star merger event
GW170817 was characterized by an early-time bright peak in optical and UV
bands. Such blue kilonova is commonly interpreted as a signature of weak
$r$-process nucleosynthesis in a fast expanding wind whose origin is currently
debated. Numerical-relativity simulations with microphysical equations of
state, approximate neutrino transport, and turbulent viscosity reveal a new
mechanism that can power the blue kilonova. Spiral density waves in the remnant
generate a characteristic wind of mass ${sim}10^{-2}~M_{odot}$ and velocity
${sim}0.2$c. The ejected material has electron fraction mostly distributed
above $0.25$ being partially reprocessed by hydrodynamic shocks in the
expanding arms. The combination of dynamical ejecta and spiral-wave wind can
account for solar system abundances of $r$-process elements and early-time
observed light curves.

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