Multiwavelength Radiation from the Interaction between Magnetar Bursts and Companion Star in a Binary System

TL;DR

This paper investigates electromagnetic signals generated by magnetar bursts interacting with a companion star in a binary system, highlighting potential observable signatures across optical, UV, and X-ray bands.

Contribution

It introduces a model for electromagnetic emissions from magnetar-binary interactions, emphasizing the dominance of persistent and burst re-emission signals in different magnetar ages.

Findings

Persistent preburst radiation is dominant in newborn magnetars, mainly in optical and UV bands.

Re-emission from burst interaction surpasses preburst radiation in older magnetars.

Transient signals could be detectable in nearby galaxies with current telescopes.

Abstract

Magnetars are young, highly magnetized neutron stars that are associated with magnetar short bursts (MSBs), magnetar giant flares (MGFs), and at least some fast radio bursts (FRBs). In this work, we consider a magnetar and a main sequence star in a binary system and analyze the properties of the electromagnetic signals generated by the interaction between the magnetar bursts and the companion star. During the preburst period, persistent radiation could be generated by the interaction between the $e^+e^-$-pair wind from the magnetar and the companion or its stellar wind. We find that for a newborn magnetar, the persistent preburst radiation from the strong magnetar wind can be dominant, and it is mainly at the optical and ultraviolet (UV) bands. For relatively old magnetars, the re-emission from a burst interacting with the companion is larger than the persistent preburst radiation and the luminosity of the companion itself. The transient re-emission produced by the heating process has a duration of $0.1 - 10^5 {\rm~s}$ at the optical, UV, and X-ray bands. Additionally, we find that if these phenomena occur in nearby galaxies within a few hundred kiloparsecs, they could be detected by current or future optical telescopes.