http://arxiv.org/abs/1812.06631
Super-Chandrasekhar remnants of double white dwarf mergers could sometimes collapse into a rapidly rotating neutron star, accompanying with a mass ejection of a few times $0.01M_{\odot}$. Bright optical transient emission can be produced by the ejecta due to heating by radioactivities and particularly by energy injection from the neutron star. Since the merger remnants before collapse resemble a star evolving from asymptotic giant branch phase to planetary nebula phase, an intense dusty wind is considered to be driven about several thousand years ago before the collapse and surround the remnant at large radii. Therefore, the optical transient emission can be somewhat absorbed and scattered by the dusty wind, which can suppress the peak emission and cause a scattering plateau in optical light curves. Several years later, as the ejecta finally catches up with the wind material, the shock interaction between them can further give rise to a detectable radio transient emission on a timescale of several ten days. Discovery of and observations to such dust-affected optical transients and shock-driven radio transients can help to explore the nature of super-Chandrasekhar merger remnants and as well as the density and type ratios of double white dwarf systems, which is benefit for assessing their gravitational wave contributions.
Y. Yu, A. Chen and B. Wang
Tue, 18 Dec 18
35/91
Comments: 7 pages, 6 figures
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