Internal shock model for the X-ray flares of Swift J1644+57

TL;DR

This paper proposes an internal shock model to explain the X-ray flares of Swift J1644+57, attributing the flares to collisions of relativistic shells and their synchrotron emission, matching observed spectral energy distributions.

Contribution

It introduces a detailed internal shock model for Swift J1644+57's X-ray flares, linking shell collisions to observed emissions and spectral features.

Findings

The spectral energy distribution can be explained by the internal shock model.

Relativistic reverse shocks dominate X-ray emission.

Forward shocks dominate infrared and optical emissions.

Abstract

Swift J1644+57 is an unusual transient event, likely powered by the tidal disruption of a star by a massive black hole. There are multiple short timescales X-ray flares were seen over a span of several days. We propose that these flares could be produced by internal shocks. In the internal shock model, the forward and reverse shocks are produced by collisions between relativistic shells ejected from central engine. The synchrotron emission from the forward and reverse shocks could dominate at two quite different energy bands under some conditions, the relativistic reverse shock dominates the X-ray emission and the Newtonian forward shock dominates the infrared and optical emission. We show that the spectral energy distribution of Swift J1644+57 could be explained by internal shock model.