Full transport model of GW170817like disk produces a blue kilonova
Abstract
The 2017 detection of the inspiral and merger of two neutron stars in gravitational waves and gamma rays was accompanied by a quickly reddening transient. Such a transient was predicted to occur following a rapid neutron capture (rprocess) nucleosynthesis event, which synthesizes neutronrich, radioactive nuclei and can take place in both dynamical ejecta and in the wind driven off the accretion torus formed after a neutron star merger. We present the first threedimensional general relativistic, full transport neutrino radiation magnetohydrodynamics simulations of the black holeaccretion diskwind system produced by the GW170817 merger. We show that the small but nonnegligible optical depths lead to neutrino transport globally coupling the disk electron fraction, which we capture by solving the transport equation with a Monte Carlo method. The resulting absorption drives up the electron fraction in a structured, continuous outflow, with electron fraction as high as Y_{e}∼ 0.4 in the extreme polar region. We show via nuclear reaction network and radiative transfer calculations that nucleosynthesis in the disk wind will produce a blue kilonova.
 Publication:

Physical Review D
 Pub Date:
 July 2019
 DOI:
 10.1103/PhysRevD.100.023008
 arXiv:
 arXiv:1905.07477
 Bibcode:
 2019PhRvD.100b3008M
 Keywords:

 Astrophysics  High Energy Astrophysical Phenomena;
 General Relativity and Quantum Cosmology
 EPrint:
 Phys. Rev. D 100, 023008 (2019)