A Pulsar Wind Nebula Embedded in the Kilonova AT2017fgo Associated with GW 170817/GRB 170817A

Jia Ren, Da-Bin Lin, Lu-Lu Zhang, Xiao-Yan Li, Tong Liu, En-Wei Liang

Published 2019-05-12Version 1

The first detected gravitational wave GW 170817 from a binary neutron star merger is associated with an important optical transient AT2017fgo, which is a direct observation of kilonova. The recent observations suggest that the remnant compact object of the binary neutron star merger associated with GW 170817/GRB 170817A may be a stable long-lived magnetized neutron star. In this situation, there would be a pulsar wind nebula (PWN) embedded inside the dynamic ejecta. Then, we study the effect of the PWN emission on the observed light curves and radiation spectra. It is found that the characteristic emission of the embedded PWN quickly evolves. For the multi-band and longterm observations of AT2017fgo, we find that the dynamic ejecta with a PWN emission can fit the observational data very well, especially for the light curves at $t\sim 5$ days and those in the late phase. Our fitting result suggests that a PWN is embedded in the AT2017fgo.