Revisiting X-ray Afterglows of Jetted Tidal Disruption Events with the External Reverse Shock

TL;DR

This study models the external reverse shock in relativistic jets of jetted tidal disruption events to explain their X-ray afterglows, incorporating jet dynamics, energy injection, and emission processes, and compares results with observed data.

Contribution

It introduces a detailed reverse shock model for TDE jets that accounts for continuous energy injection and explains observed X-ray light curves and spectra.

Findings

Reverse shock can explain X-ray light curves of four jetted TDEs.

Rapid X-ray decline is due to jet break and engine shutdown.

Model predicts potential gamma-ray and neutrino signals.

Abstract

We investigate the external reverse shock region of relativistic jets as the origin of X-ray afterglows of jetted tidal disruption events (TDEs) that exhibit luminous jets accompanied by fast-declining non-thermal X-ray emissions. We model the dynamics of jet propagating within an external density medium, accounting for continuous energy injection driven by accretion activities. We compute the time-dependent synchrotron and inverse Compton emissions from the reverse shock region. Our analysis demonstrates that the reverse shock scenario can potentially explain the X-ray light curves and spectra of four jetted TDEs, AT 2022cmc, Swift J1644, Swift J2058, and Swift J1112. Notably, the rapid steepening of the late-stage X-ray light curves can be attributed jointly to the jet break and cessation of the central engine as the accretion rate drops below the Eddington limit. Using parameters obtained from X-ray data fitting, we also discuss the prospects for $\gamma$-ray and neutrino detection.