Supernova and prompt gravitational-wave precursors to LIGO gravitational-wave sources and short-GRBs

Abstract

Binary black-holes (BHs) and binary neutron-stars (NSs) mergers had been recently detected through gravitational-wave (GW) emission, with the latter followed by post-merger electromagnetic counterparts, appearing seconds up to weeks after the merger. While post-merger electromagnetic counterparts had been anticipated theoretically, very little electromagnetic precursors to GW-sources had been proposed, and non observed yet. Here we show that a fraction of ${\rm a}\,{\rm few\times}10^{-4}-10^{-1}$ of LIGO GW-sources and short-GRBs, could be preceded by supernovae-explosions years up to decades before the merger. Each of the BH/NS-progenitors in GW-sources are thought to form following a supernova, likely accompanied by a natal velocity-kick to the newly born compact object. The evolution and natal-kicks determine the orbits of surviving binaries, and hence the delay-time between the birth of the compact-binary and its final merger through GW-emission. We use data from binary evolution population-synthesis models to show that the delay-time distribution has a non-negligible tail of ultra-short delay-times between 1-100 yrs, thereby giving rise to potentially observable supernovae precursors to GW-sources. Moreover, future LISA/DECIGO GW space-detectors will enable the detection of GW-inspirals in the pre-mergers stage weeks to decades before the final merger. These ultra-short delay-time sources could therefore produce a unique type of promptly appearing LISA/DECIGO-GW-sources accompanied by \emph{coincident} supernovae. The archival (and/or direct) detection of precursor (coincident) SNe with GW and/or short-GRBs will provide unprecedented characterizations of the merging-binaries, and their prior evolution through supernovae and natal kicks, otherwise inaccessible through other means.