A Unified Theory of Jetted Tidal Disruption Events: From Promptly Escaping Relativistic to Delayed Transrelativistic Jets

TL;DR

This paper presents a unified theory explaining the diverse behaviors of jetted tidal disruption events (TDEs) based on the misalignment between the star's orbit and the black hole's spin, affecting jet escape and observable emissions.

Contribution

It introduces a model linking disk/jet misalignment and precession to jet escape conditions, explaining the variety of TDE jet observations and their timing.

Findings

Misalignment causes Lense-Thirring precession and large-scale winds.

Critical jet efficiency determines escape success depending on alignment.

Different alignment mechanisms lead to distinct observational signatures.

Abstract

Only a tiny fraction ~ 1% of stellar tidal disruption events (TDE) generate powerful relativistic jets evidenced by luminous hard X-ray and radio emissions. We propose that a key property responsible for both this surprisingly low rate and a variety of other observations is the typically large misalignment {\psi} between the orbital plane of the star and the spin axis of the supermassive black hole (SMBH). Such misaligned disk/jet systems undergo Lense-Thirring precession together about the SMBH spin axis. We find that TDE disks precess sufficiently rapidly that winds from the accretion disk will encase the system on large scales in a quasi-spherical outflow. We derive the critical jet efficiency {\eta} > {\eta}crit for both aligned and misaligned precessing jets to successfully escape from the disk-wind ejecta. As {\eta}crit is higher for precessing jets, less powerful jets only escape after alignment with the SMBH spin. Alignment can occur through magneto-spin or hydrodynamic mechanisms, which we estimate occur on typical timescales of weeks and years, respectively. The dominant mechanism depends on {\eta} and the orbital penetration factor \b{eta}. Hence depending only on intrinsic parameters of the event {{\psi},{\eta},\b{eta}}, we propose that each TDE jet can either escape prior to alignment, thus exhibiting erratic X-ray light curve and two-component radio afterglow (e.g., Swift J1644+57) or escape after alignment. Relatively rapid magneto-spin alignments produce relativistic jets exhibiting X-ray power-law decay and bright afterglows (e.g., AT2022cmc), while long hydrodynamic alignments give rise to late jet escape and delayed radio flares (e.g., AT2018hyz).