Impact of Pulsar and Fallback Sources on Multifrequency Kilonova Models. (arXiv:1904.05934v1 [astro-ph.HE])

Impact of Pulsar and Fallback Sources on Multifrequency Kilonova Models. (arXiv:1904.05934v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Wollaeger_R/0/1/0/all/0/1">Ryan T. Wollaeger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fryer_C/0/1/0/all/0/1">Chris L. Fryer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fontes_C/0/1/0/all/0/1">Christopher J. Fontes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lippuner_J/0/1/0/all/0/1">Jonas Lippuner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vestrand_W/0/1/0/all/0/1">W. Thomas Vestrand</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mumpower_M/0/1/0/all/0/1">Matthew R. Mumpower</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Korobkin_O/0/1/0/all/0/1">Oleg Korobkin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hungerford_A/0/1/0/all/0/1">Aimee L. Hungerford</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Even_W/0/1/0/all/0/1">Wesley P. Even</a>

We explore the impact of pulsar electromagnetic dipole and fallback accretion
emission on the luminosity of a suite of kilonova models. The pulsar models are
varied over pulsar magnetic field strength, pulsar lifetime, ejecta mass, and
elemental abundances; the fallback models are varied over fallback accretion
rate and ejecta mass. For the abundances, we use Fe and Nd as representatives
of the wind and dynamical ejecta, respectively. We simulate radiative transfer
in the ejecta in either 1D spherical or 2D cylindrical spatial geometry. For
the grid of 1D simulations, the mass fraction of Nd is 0, $10^{-4}$, or
$10^{-3}$ and the rest is Fe. Our models that fit the bolometric luminosity of
AT 2017gfo (the kilonova associated with the first neutron star merger
discovered in gravitational waves, GW170817) do not simultaneously fit the B,
V, and I time evolution. However, we find that the trends of the evolution in B
and V magnitudes are better matched by the fallback model relative to the
pulsar model, implying the time dependence of the remnant source influences the
color evolution. Further exploration of the parameter space and model
deficiencies is needed before we can describe AT 2017gfo with a remnant source.

We explore the impact of pulsar electromagnetic dipole and fallback accretion
emission on the luminosity of a suite of kilonova models. The pulsar models are
varied over pulsar magnetic field strength, pulsar lifetime, ejecta mass, and
elemental abundances; the fallback models are varied over fallback accretion
rate and ejecta mass. For the abundances, we use Fe and Nd as representatives
of the wind and dynamical ejecta, respectively. We simulate radiative transfer
in the ejecta in either 1D spherical or 2D cylindrical spatial geometry. For
the grid of 1D simulations, the mass fraction of Nd is 0, $10^{-4}$, or
$10^{-3}$ and the rest is Fe. Our models that fit the bolometric luminosity of
AT 2017gfo (the kilonova associated with the first neutron star merger
discovered in gravitational waves, GW170817) do not simultaneously fit the B,
V, and I time evolution. However, we find that the trends of the evolution in B
and V magnitudes are better matched by the fallback model relative to the
pulsar model, implying the time dependence of the remnant source influences the
color evolution. Further exploration of the parameter space and model
deficiencies is needed before we can describe AT 2017gfo with a remnant source.

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