Evidence for Two-Component Jet in Sw J1644+57

TL;DR

This paper presents evidence for a two-component relativistic jet in Sw J1644+57, explaining radio re-brightening and X-ray quasi-periodic oscillations through a structured jet model involving different launching mechanisms.

Contribution

It provides observational evidence supporting a two-component jet model and links it to specific quasi-periodic features in X-ray and radio data.

Findings

Radio re-brightening explained by two-component jet model

X-ray QPOs interpreted as effects of a precessing outer jet and a narrower jet

Structured jet origin linked to Blandford-Znajek and Blandford-Payne mechanisms

Abstract

The continued observations of Sw J1644+57 in X-ray and radio bands accumulated a rich data set to study the relativistic jet launched in this tidal disruption event. We find that the re-brightening feature in the radio light curve can be naturally explained by the two-component jet model. The possible origin of this structured jet are the Blandford-Znajek and Blandford-Payne mechanisms. We also show that this two-component jet model can interpret the two kinds of quasi-periodic variations in the X-ray light curve: a 200 second quasi-periodic oscillation (QPO) and a 2.7-day quasi-periodic variation. The latter is interpreted by a precessing outer jet launched near the Bardeen-Petterson radius of a warped disk. The $\sim$ 200s QPO could be associated with a second, narrower jet sweeping the observer line-of-sight periodically, which is launched from a spinning black hole in the misaligned direction with respect to the black hole's angular momentum.