2015/11/30 by Shao-Ze Li, Yun-Wei Yu
Physics and Astronomy · #Astrophysical Phenomena and Observations #Breakout #Ejecta #Gamma-ray burst #Gamma-ray bursts and supernovae #Gravitational wave #Luminosity #Neutron star #Pulsars and Gravitational Waves Research #Shock (circulatory) #Shock wave #astro-ph.HE #astro-ph.SR
paper · pdf · doi:10.3847/0004-637x/819/2/120
7 pages, 4 figures, accepted by ApJ
arxiv created 2016/01/15 · openalex publication_date 2016/03/07 · arxiv updated 2016/03/23 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
ABSTRACT A supra-massive neutron star (NS) spinning extremely rapidly could survive from a merger of an NS-NS binary. The spin-down of this remnant NS that is highly magnetized could power the isotropic merger ejecta to produce a bright mergernova emission in the ultraviolet/optical bands. Before the mergernova, the early interaction between the NS wind and the ejecta could drive a forward shock propagating outward into the ejecta. As a result, a remarkable amount of heat can be accumulated behind the shock front and the final escape of this heat could produce a shock breakout emission. We describe the dynamics and thermal emission of this shock with a semi-analytical model. It is found that a few hours after the merger, by leading the mergernova emission as a precursor, sharp and luminous breakout emission appears mainly in soft X-rays, with a luminosity of . Therefore, the detection of such an X-ray precursor could provide evidence for identifying NS-powered mergernovae and distinguishing them from radioactivity-powered novae (i.e., kilonovae or macronovae). The discovery of NS-powered mergernovae could finally help to confirm the gravitational wave signals due to the mergers and the existence of supra-massive NSs.