Constrain the ejecta of GW 170817

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GW 170817 is the first GW event together with its electromagnetic counterparts, imply that neutron merger. We consider a simple model for the nonthermal emission from GW170817, in which a quasi-spherical ejecta is released in the merger event, with the kinetic energy distributed over the momentum. The ejecta drives a shock into the medium and gives rise to synchrotron radiation.

Constrain the ejecta of GW 170817
Huang Y., Li Z., 2018, ApJ, 862, 162
Full Paper: https://arxiv.org/

GW 170817 is the first GW event together with its electromagnetic counterparts, imply that neutron merger. We consider a simple model for the nonthermal emission from GW170817, in which a quasi-spherical ejecta is released in the merger event, with the kinetic energy distributed over the momentum. The ejecta drives a shock into the medium and gives rise to synchrotron radiation.

  • Using multi-band observations, we constrain k to be ~6.7;

  • The total kinetic energy to be (0.3-5)E51 erg；

  • The slowest ejecta velocity is ~ (0.7-0.8)c, and the fastest ejecta has a Lorentz factor of ~ 4-7;

  • These properties may not favor the sub-relativistic dynamical ejecta responsible to the thermal kilonova emission.

  • The co-existence of the nonthermal and thermal kilonova emission implies that two corresponding ejecta are ejected at different angles.