Neutron star natal kicks: Collisions, $\mu$TDEs, faint SNe, GRBs and GW sources with preceding electromagnetic counterparts

TL;DR

This paper investigates the dynamical effects of neutron star natal kicks on binary systems, exploring outcomes like collisions, tidal disruption events, and the formation of various astrophysical phenomena, with implications for gravitational wave sources and electromagnetic counterparts.

Contribution

It provides a detailed analysis of the possible outcomes of neutron star natal kicks using population synthesis models, including collision rates, tidal disruption events, and implications for GW and EM signals.

Findings

Neutron star kicks can lead to direct collisions with companions.

Rates of micro tidal disruption events ($$TDEs) are significant.

Potential formation of short-lived BH-NS binaries and associated GW sources.

Abstract

Based on the observed high velocity of pulsars it is thought that neutron stars (NSs) receive a significant velocity kick at birth. Such natal kicks are considered to play an important role in the the evolution of binary-NS systems. The kick given to the NS (together with the effect of mass loss due to the supernova explosion of the NS progenitor) may result in the binary disruption or lead to a significant change of the binary orbital properties. Here we explore in detail the dynamical aftermath of natal kicks in binary systems, determine their possible outcomes and characterize their relative frequency, making use of analytic arguments and detailed population synthesis models. In a fraction of the cases the kick may cast the NS in such a trajectory as to collide with the binary companion, or pass sufficiently close to it as to disrupt it (micro tidal disruption event; $\mu$TDE), or alternatively it could be tidally-captured into a close orbit, eventually forming an X-ray binary. We calculate the rates of direct post-kick physical collisions and the possible potential production of Thorne-Zytkow objects or long-GRBs through this process, estimate the rates X-ray binaries formation and determine the rates of $\mu$TDEs and faint supernovae from white dwarf disruptions by NSs. Finally we suggest that natal kicks can produce BH-NS binaries with very short gravitational-wave merger time, possibly giving rise to a new type of promptly appearing eLISA gravitational wave (GW) sources, as well as producing aLIGO binary-merger GW sources with a unique (likely type Ib/c) supernova electromagnetic counterpart which precedes the GW merger.