1307.2943 (Doron Grossman et al.)

The longterm evolution of neutron star merger remnants II: radioactively powered transients    [PDF]

Doron Grossman, Oleg Korobkin, Stephan Rosswog, Tsvi Piran

We use 3D hydrodynamic simulations of the longterm evolution of neutron star merger ejecta to predict the light curves of electromagnetic transients that are powered by the decay of freshly produced r-process nuclei. For the dynamic ejecta that are launched by tidal and hydrodynamic interaction we adopt gray opacities of 10 cm$^2$/g, as suggested by recent studies. For our reference case of a 1.3-1.4 $m_\odot$ merger we find a broad IR peak 2-4 days after the merger. The peak luminosity is $\approx 2\times 10^{40}$ erg/s for an average orientation, but increased by up to a factor of 4 for more favorable binary parameters and viewing angles. These signals are rather weak and hardly detectable within the large error box (~100 deg$^2$) of a GW trigger. A second electromagnetic transient results from neutrino-driven winds. These winds produce "weak" r-process material with 50View original: http://arxiv.org/abs/1307.2943