Bright "merger-nova" from the remnant of a neutron star binary merger: A signature of a newly born, massive, millisecond magnetar

Understand

A massive millisecond magnetar may survive a merger of a neutron star (NS) binary, which would continuously power the merger ejecta.

• We develop a generic dynamic model for the merger ejecta with energy injection from the central magnetar.
• The ejecta emission (the "merger-nova") powered by the magnetar peaks in the UV band and the peak of lightcurve progressively shifts to an earlier epoch with increasing frequency.
• A magnetar-powered mergernova could have an optical peak brightness comparable to a supernova, which is a few tens or hundreds times brighter than the radioactive-powered merger-novae (the so-called macro-nova or kilo-nova).