Models of Kilonova/macronova emission from black hole-neutron star mergers [HEAP]

http://arxiv.org/abs/1601.07711


Black hole-neutron star mergers are among the promising gravitational-wave sources for ground-based detectors, and gravitational waves from black hole-neutron mergers are expected to be detected in the next few years. Simultaneous detection of electromagnetic counterparts with gravitational-wave detection provides rich information about the merger events. Among the possible electromagnetic counterparts from the black hole-neutron merger, the emission powered by the decay of radioactive r-process nuclei, so called kilonova/macronova, is one of the best targets for follow-up observation. We derive fitting formulas for the mass and the velocity of ejecta from a generic black hole-neutron merger based on recently performed numerical relativity simulations. We combined these fitting formulas with a new semi-analytic model for a black hole-neutron kilonova/macronova lightcurve which reproduces the results of radiation-transfer simulations. Specifically, the semi-analytic model reproduces the result of each band magnitude obtained by the radiation transfer simulations within ~1 mag. By using this semi-analytic model, we found that, at 400 Mpc, the kilonova/macronova is as bright as 22-24 mag for the cases with a small chirp mass and a high black hole spin, and >28 mag for a large chirp mass and a low black hole spin. We also apply our model to GRB130603B as an illustration, and show that a black hole-neutron merger with a rapidly spinning black hole and a large neutron star radius is favored.

Read this paper on arXiv…

K. Kawaguchi, K. Kyutoku, M. Shibata, et. al.
Fri, 29 Jan 16
13/52

Comments: 16 pages, 9 figures, 2 tables, submitted to ApJ